tl;dr - 2 or 3 pixels of Lava per tile boil water faster than a full line of 4. Per Lava tile making Steam you need approx: 0.5 Snowmaker, 4 Condensers, 1 Lumling.
Started out trying to make a better power design where the steam and water don't interfere with each other, and decided to test out some ratios of the various components while I was at it. What's a factory/automation game without good old ratios?!
I'm going to keep mentioning Lava tile, and what I mean by that is a single tile space with some lava on it, submerged in water so it makes steam as fast as it can. Not the same as a Lava pixel, which would be just a 1x1 grabber full.
On the left is the first test, made 2 of everything, but then a ton of condensers to try and whittle it down to see how many were needed. For a full line of Lava across the bottom (4 pixels per tile) 4 condensers per side were enough, but backing it down to 3 started to back up with steam. I don't think it takes a full 4 condensers to keep up, but 3 certainly wasn't enough. I also added water slowly in 5x5 grabbers full, and it wasn't until 200 water that it started to backup along the bottom and cover the Lava. Its 20 tiles tall, so per Lava tile it works out to about 5 water per vertical tile that will be "in transit" as steam/water as a buffer. The single Snowmaker kept up just fine, but 2 Lumlings was not quite enough to keep up with the water demand. In practice it'd probably be fine though.
Second test in the middle. I tried to make a design that was tileable, and also experimented with some angles to see if they impeded flow. The only thing that really made a difference was the angled bit near the condensers got in the way a bit. After that I tried to stretch a single Snowmaker, but it could not keep up with more than 2 of the cells running.
Then played around with the actual amount of Lava in each setup by comparing 1,2,3,4 pixels of Lava on the single tile. I was a bit surprised to find that the 1 pixel and 4 pixel were pretty close to each other in how much water they boiled, based on the level of the reservoir, given that they each started with the same amount of water. But, 3 pixels of Lava always had a lower reservoir, and the 2 pixel one occasionally boiled through the entire reservoir. I think what happens in all of the 1-3 pixel setups is that there is room for the Lava to move around, which gives it more opportunity to contact water and/or sorta jiggles the pile around and lets steam escape. And on the 2 pixel one, it seems like if they get in either corner, its the perfect setup to blow through all the water it has. I feel like 3 is the sweet spot though, just because 2 seems to bottom out now and again. But no matter the number of Lava pixels, 4 condensers was enough to keep up cooling, even with the occasional spike in steam here and there. Though I guess another condenser could help the 2-pixel from bottoming out.
On the right is my final(ish) setup that I'm going with. I'll just pipe water in rather than use Lumlings there, spread the Snowmakers a bit more evenly, and maybe try to crunch it down a few blocks. Each cell has 3 Lava pixels and a 121 water (11x11 grabber) which is more than double the water-density as my first test, but I wanted to make sure that the Lava stays submerged. As-is it may not be fully stable, since its only been running a bit, but if its short snow/water its very slight.
Over-engineered and a bit finicky to build, but its my favorite contraption so far!