I'm finishing my 40x56 right now. Im drywalling, plywood is rediculous right now and I hate the way it looks. Drywall is cheap and doesn't echo. Check out inferred tube heaters quiet and very efficient. I went with bat r26 in a 2x6 wall. Spray foam is nice but I can buy alot of propane for the price difference. It's also a nightmare to rip that crap apart if you ever add on... Don't ask... Nice shop you have,..