I'm not sure what the labile pool is, but I do understand that the body utilizes proteins uh, more effectively? in the hours after the workout, and there is an advantage to protein uptake if it is allready in the body before the workout, so I start sipping 1/2 hr. early and through the workout. If not, I do the whole blenderful right after the workout, then eat solid food later.
My experience with supersaturating skim powder was to create a dense cream mush. I don't know how much I used though.