I cheat a bit by not brewing high abv beers in 5 gallon batches. Generally if it will be a high gravity beer I don't brew more than 3 gallons and often less (I like having some on hand but don't drink high abv beers often). That allows me to use my 6.5 gallon cooler as a mash tun and then I mash with the full volume of water. I caramelized some of the first runnings and use it to bring the mash temp up to where it would normally be for mash out (I use one of the calculators to get the volume I need). Varlouf a bit and into the pot it goes.
