I only have three chickens right now and they free range most of the day so I don't have to make very much at a time. The current recipe is a tablespoon of leftover fermented feed from the day before, to which I add enough water to equal 10 fluid ounces, and between 6 and 8 ounces of dry feed. My kids broke my kitchen scale last week or I would weigh it tomorrow to see exactly.
I've been trying to find the maximum amount of water I can use that also ensures that the chickens will consume the fines. I may try a 48-hour ferment to just to see what happens and if the grains will absorb more water in two days vs. one. I'm not sure at what point the grains will become fully saturated, but I want to find that point because I noticed that on the fermented feed, they drink a lot less water and I'm hoping that being better hydrated will help them get through the heat better.
I'll be very interested in what you end up doing, as I can see that you're in Phoenix and your summer temps are much higher than ours!!!