We DS out of 35 gallon tank on the trailer. 32 gallons of SH and 28 ounces of Elemonator. Usually lasts 4-5 days on two houses a day. Sometimes have to fill it a little earlier.
I don’t do roofs either, but not by choice.
There’s always a gallon of Elemonator, 3.5 gallons of degreaser, 10 lbs of oxalic powder, a Zep spray bottle half filled with F9, half water, Barkeeper’s Friend Soft Cleaner, and magic erasers on the trailer. That’s all we use 95% of the time.
F9 and EBC only come out of the shop if the customer has agreed to pay a premium for it before hand.