I agree with you on going nutz from the start. I am in the same boat as you; I want to start a brewery someday, so I’ve bought things way larger than I really need. I am going to build a MLT with a false bottom and a 9000w rims system to hold temp, and just insulate the thing with some wrap of some sort. Just got the rims, and am about to try my first batch of 10 gallon with it, and intend to do it with 50 later. If you can find any kind of ss and insulate it will work, I’ve seen people using sinks and weird **** like that, but it works well if its insulated.