I often do a 60m mash with 3 gallons followed by a shorter mash at a different temperature and a sparge. In an insulated mash tun. I don't think it matters that much, and you can get away with a single infusion mash and a good sparge with modern malts. I just find a medium mash followed by a high mash to work well when extracting. I guess breweries did that kind of stuff to get the most out of their grain. The grists are very interesting, though!