I would use deep 4” square steel boxes with two gang mud rings everywhere. Mount the boxes 8’5/8” down from the ceiling. You will most likely use 5/8” Sheetrock on the ceiling and work your way down with the sheeting. At 8’5/8” the bottom of the box should be on the plywood seem. I realize you...
I heat 2400sq feet with a 40 gallon heater. I ran a 30 amp circuit to each heater element so they can both run at once. It makes no difference how many gallons the tank is,only how many watts of heat your putting into the system. If the tank is in the shop it doesn't matter if the tank is...