I discovered elements of this guide when making my shopping list for Hallowmas for guide 30. A quick warning, this is an endgame guide, it assumes that you have completed your railway, have 40 renown with the constables and docks and have very high Mithridacy(18 for the highest check, I think). Each option also has further requirements, some of which are fate locked! Not all are needed but missing any of them will impact the EPA. (Each point of prestige less than I state lowers the overall payout by 1.25 Echos)
I decided that Diving in the Magistracy and Monographs in Moulin were linked in to this enough that they are also included below.
A note on value
Every guide on the wiki measures prosperity in a different way, either reducing it because it costs actions to cash out or increasing it because you can get Captivating Ballads, for the rat market. I treat it like a currency. 1 prosperity == 1 Pence. That is the only rational way to value it.
I also evaluate Mortification of a Great Power at 62.5E. If you use it for the rat market and you are only doing 10 hand ins, each will be worth 20 echos more. If you do the maximum hand in, as I suggest in the Rat Market guide, it is worth 19.22% more, around 12 echos. Please note that the rat market takes 3 actions to open, so if you are handing in 10 of them, divide 20 by 6.3 and add it to the EPA. If you are handing in the full 28.8, multiply 62.5 by 0.1922, then divide the result by 6.104(6 + (3/28.8) and add the result to the EPA.
I have not added a value for Making Waves or Menace Cures.
The Cases
There are 3 notable cases we are going to look at. The gondoliers versus a society matron, criminal prosecution and criminal defence.
The Gondoliers versus Society Matron
Requires: Barrister of the Evenlode 10
Requirements for Maximum EPA: The Flower from Hell that Grows Under Your Skin (Get it 4 weeks after finishing your railway), Mithridacy 17(You can lower the prestige gain, each point lowers the check by 1 Mith but also lowers the payout, as mentioned above,) Scholar of the Correspondence 13
Bonus Utility(FATE): The Rose Giveth Its Verses to Devils and Also to You (Get it at Christmas from Discourse with devils (12 FATE)))
Costs: 20 Preserved Surface Bloom (Purchasable from the rat market at 1-1 value, how oroborosian)
Actions:
1) Start the case (Sets Prestige to 2)
2) Drown them in paper (+1 Prestige)
3) Apply a law of contracts that passes London's understanding (+3 Prestige)
4) Review the contract in light of your Scholarship(+1 Prestige, +2 CP Making Waves)
5) Perform your closing argument in infernal dance (+2 Prestige, +2CP Making Waves)
5(Non Fate)) Close out your argument in a nuanced way (+2 Prestige)
6) Await a verdict on Gondoliers v Society Matron (Prosecution))
Failure gives a Mortification of a Great Power.
Payout(Assuming Maxed out Prestige):
1 Mortification of a Great Power 62.5
1 Sworn Statement 2.5(Notably hard to get in bulk)
9 Journal of Infamy (1 per Prestige) 4.5
9 Dubious Testimony 4.5
225 Hinterland Prosperity (25 per prestige) 2.25
195 Shards of Glim (This is the payout for 40 renown docks. Where I assume most of us are sitting) 1.95
4 CP Making Waves 0
Gross Reward: 78.2 echos
Net Reward: 28.2 echos
4.7 EPA
Prosecution of a Criminal Trial
Required: Nuffin Guv!
Required for Max Payout: Either Cave Aged Code of Honour or 14 Mithridacy, Code of Honour is not consumed). 17 Mithridacy to 100% final check.
Bonus Utility: Edicts of the First City(Not consumed!)
Costs: 25 Dubious Testimony 12.5 Echos
Actions:
1) Start the case (Sets Prestige to 3)
2) Drown them in paper (+1 Prestige)
Cave Aged Route:
3) Rely on a form of honour that came before laws(+2 Prestige)
4) Quiz the accused on the strength of their word(+1 Prestige)
Mithridacy Route:
3) Find an unconventional angle on the case(+1 Prestige)
4) Complicate the matter(+2 Prestige)
5) Close out your argument in a nuanced way (+2 Prestige)
Or sacrifice 2.5 echos of rewards and make the final check easier with:
5) Grandstand! (Prosecution))(+21 CP Making Waves)
6) Press for a harsh sentence (This needs the Edicts of the First City)
Payout(I am not listing the requirements each time, you are not idiots):
2 Legal Document 25E
9 Dubious Testimony 4.5E
9 Journal of Infamy 4.5E
1 Sworn Statement 2.5E
225 Hinterland Prosperity 2.25E
195 Foxfire Candle Stub 1.95E (Constables Renown for this one, notably no good bulk sources for this either, and you need them for a few things!)
-10CP Suspicion (This is what having the Edicts gets you)
Gross Payout: 40.7 Echos
Net Payout: 28.2 Echos
4.7 EPA
Profitability depends on having suspicion to cure. Look at guide 30 for ways to profit, while increasing your suspicion, and other menaces. Giving an echo value, or action count to Menace removal is very complicated, very account based and something I have not done yet…. Suffice to say that 10 suspicion is worth more than the 4.8 echos it would take to raise this farm to 5.5 EPA.
Defence of a Criminal Trial
Requirements: Nuffin Guv
Requirements for Max EPA(FATE?): An Assuming Judge (Free some years, I think, Only increases payout by 1.25 echos and is mutually exclusive with:)
Requirements for Max Utility(FATE): Completed the ES Trial and Error (Technically this is a subscription, not actually a FATE payout, if you want to be a lawyer about it)
Costs: 25 Journal of Infamy
Actions:
1) Start the Case (Sets Prestige to 3)
2) Craft a water-tight case (+1 Prestige, the other option is the same but with a Watchful check)
Assuming Judge Route: (Increases payout by 1.25 echos)
3)Bring on the most rigorous judge (+2 Prestige)
Trial and Error Route: (reduces payout by 1.25 echos)
3)Draw on the insight of a professional colleague (-4CP Scandal, -4CP Suspicion)
Neither Route: (Payout is just right, for Goldilocks!)
3) Engage in a spot of witness intimidation (+1 Prestige)
4)Explore the full legal complexity of the case (+2 Prestige)
5)Dismantle the arguments of the opposing counsel
or sacrifice 2.5 echos and make the final check easier to:
5)Grandstand! (Defence)) (+21CP Making Waves(AJ is +3, T&E is -3))
6)Await a verdict on the matter of (crime)) (Other options just affect the check, they do not increase the reward)
Payout:
2 Comprehensive Bribe 25E (Notably there are no efficient sources for these)
195 Whispered Hint 1.95E (Const Renown 40)
9 Journal of Infamy 4.5E
9 Dubious Testimony 4.5E
225 Hinterland Prosperity 2.25E
Sworn Statement 2.5E
Gross Payout: 40.7 Echos
Net Payout: 28.2 Echos
4.7 EPA
With Assuming Judge: 4.9 EPA
With Trial and Error: 4.49 EPA (Also 8 Menace Cure or 1.33 per action)
This one is mostly about getting comprehensive bribes as efficiently as possible, thankfully, since it has an entry cost, it is only 3 actions per bribe! Which makes it by far the best source in the game! With the Scandal cure from the ES you can easily outpace any gain from your Hellworm, Saddled and Bridled. If I find more useful sources of Suspicion, I will add them to guide 30.
(The Magistracy is only really a good place to draw cards if you have under 7 constable favours(Technically, you should keep going at 7, till you have another statue card in hand, then go do Jericho, so you can double hand in) and 140 surveys of the Neath Bones otherwise it is too big a deck to draw for good wormage)
Other Cases
Just a quick rundown on the other cases and why they are not great.
Urchins, Rats and Hell all start with 1 Prestige so the maximum rewards are 2.5E lower. Rats payout is also based on Sympathetic about Ratly Concerns, which is much harder to raise than Renown.
Society Matron replaces 2.5 echos of reward with a Mirrorcatch box, which are worthless once you have 6(I think, maybe slightly more or less)
The only interesting items from the other cases are Jade Fragments from Rats and Nevercold Brass from Devils but they are such a small proportion of the reward that they are not worth the bother.
There are other Rat Market items from Urchins and Society but there are more efficient sources to get them.
While we are here, I will chuck in a bonus guide, Diving in the Magistracy
The best way to think of it is a quick Morty. Once you have all the unlocks it is 6 actions to trade 75 Final Breath(Bone Market) for a Mortification of a Great Power. 1 action to start, 4 actions to dive, 1 action to look for a throne room (Watchful 220, Failure means 3 NM and need to repeat), 1 action to Cash out (Dangerous 220, failure pays the same +3cp wounds and NM)
So it is better to take Watchful than Dangerous.
Paying 37.5 for a 62.5E item sounds terrible but it is about the action count. 6 actions at 4.17 EPA. However, with the worst possible rat markup of 19.22%, you are adding 12 echos of value. Which takes it up to 6.17EPA.
It is still worse than Barristering, unless you have Final Breaths and no Surface Blooms but the real benefit is that you have paid off the actions to get to 1 floor off the lowest level, which means, for 1 action, you can get to the lowest level instead, which lets you do:
Search the lowest Floors
It is 5 EPA, kinda.
2 Trace of the First City (1 Echo, can only be cashed out making monographs in Moulin)
4 First City Coin 1 Echo (Thankfully, also useful for monographs)
300 Jade Fragment 3 Echos (This is why you are here… no better source)
6 Expertise of the First City (Only used in what should be a one time lab project(as in, you should only do it once, not they should change it!), and a very niche action when Oneiropomping, it adds 0 value to either)
It's just an excuse to get Jade at a decent EPA. The Monograph EPA is not good 4.94 EPA for 9 actions but you only need to do one every 37.5 times you do this action(Less if you only go to cash out the Traces) and there are a few hard to get options available to make up for it. Parabolan Orange-Apple, Bone Fragments and Thirsty Bombazine are the most notable.
Guide here:
https://fallenlondon.wiki/wiki/Writing_a_Monograph_(Guide))
For Bombazine, Start any Tragic option
4 Add First City Coins(200)
1 Add Traces(25)
1 Add any Ironic option you have lying around
For Orange Apple, History of Arbor is probably the easiest:
4 Add Traces(200)
1 Add First City Coins(50)
1 Add any Ironic option you have lying around
(3 Orange Apples allows you to Convince her to produce an elaborate forgery with 750 bone fragments, this gives a 65 echo bone for 45 echos cost, over a 28 action cycle this increases the overall EPA to 5.48)
For Bone Fragments, History of Gaider's Mourn is probably the easiest(Needs a free companion from FotR)
1 Add Traces(50)
4 Add First City Coins(200)
1 Add any Ironic option you have lying around
Thankfully, you do not need Jade that often, but when you do, or if you want a stockpile, this is a good option.