I received my Guppy from Joe and I must say I’m glad I took his advice and went with the extra gauge. It’s nice to know how much air is in the tank. I also got the longer hose and he was nice enough to throw in the tank armor. Now that’s how you treat a new customer.
If trying to determine tank psi with only one gauge you jsut need a " dead head", Joe's carries em as do most dealers. Sometimes keeping it simple is nice also.