I would have thought that the enzymes would be well solubilised and the grains totally rehydrated. I really cannot say what effect presolubising the alpha and beta enzymes would have on their stability as they are not really active until a much higher temperature and heat seems to be the main cause of denaturing them. I do worry a bit about possible denaturing effects of long exposure to the brew liquor and possible proteases being released but I say that from the side of having worked in laboratories that relied on enzymes being kept in as stable an environment as possible (minus 80C) so as not to be subject say to proteases that would break them down but these enzymes are in the malt and as we know that usually contains about 3 or 4 % water and the malt is usually good for two or more years. So in short you have had no issues so it must be OK, having said that I would not do that myself. From the point of view of a course crush I would hazard a guess and say it would be better than a fine crush the way you describe your method but that is a guess based purely on extraction from finer ground husk materials. I think experimentation is the only way to prove things. For example if I increase my mill gap to 1.6 mm and see no adverse effect of efficiency but an improved flow rate I will increase it again by a further 0.2mm and see what happens provided the grain is crushed. There will be a point where I see a difference so revert to the previous setting where efficiency was good.@jambop
Re: Fine/course crushing.
I like your thinking.
I have a 8hr 20c soak, before temps increase for mash. How would you expect this to impact?