This is what I consider a dumb question, especially since I can't find anything in the searches I've done here...but it is more of an experience question. My plan is to go with rubbermaid coolers as I venture into AG. My concern is size. If my *maximum* target OG is the 1.090 area, how large a vessel am I going to need? Is 7.5gal enough or is 10gal the better bet? Or maybe a combo? A 10gal mash/lauter and a 7.5gal sparge water holding tank?