Originally Posted by Kulprit
What would be the pitfalls/pros/cons of doing something like this?
Inconsistency. The coolers won't be 100% the same, and it will be a pain to make sure everything is perfectly split and balanced between the two. If you're trying to dial in the system and get results out of it that you can easily reproduce, it just throws another variable in there.
I'd suggest looking into plastic 55 gallon food-grade drums. You can usually pick those up for a song at local places that only use them once. There's a guy on craigslist by me that sells them for $15! A few layers of foil bubble wrap insulation on that and you're good to go.
When you get to that size mash tun, it holds heat pretty well just due to the sheer size of it, so that much insulation should be enough.