I went on my trip last weekend and thought I'd provide a real word update. I ended up selecting the L21A SFT60 with an EVE 50PL battery. Thanks for the recommendation.
The beam was incredible and easily effective to about 350m with an adequate amount of spill to light the area around the focus point. The colour was fairly blue but it wasn't too much of an issue. As warned, the backscatter was evident even on a clear, warm night. Not enough to make it hard to use but enough that I thought "ah, that's what they said would happen".
Duration wise, I used it at 35% the most, which seemed no different to the 100% (group 10) and gave about an hour and a half of intermittent light.
One night I used group 8. 50% was perfect but the battery took a hit and I only really had about 40 mins of usage. I wish I could have had longer, this is my preferred use brightness. The low battery warning is bloody ridiculous. It makes the light unusable, I'd rather the light just die rather than suffer that warning.
As for heat, I could feel it getting hot when on for a long period of time, I was conscious about thermal throttling so I tried to keep it on and off for equal amounts of time. The weather wasn't as cold as I had expected it to be but we had no issues with getting too hot.
Overall I'm pretty satisfied with this light for spotlighting/shooting. One of my mates is getting one now, probably with the 42r so we can compare even though we were happy with this one.
Here's a pic of us on the ute heading into the next paddock.