You guys are just complicating it with regulators and whatnot. Only thing I’d change about my setup, would be drill and tap the plastic pipe plug in my tank’s fill hole, for 1/8” pipe. Instead of drilling an extra hole in the tank for my blow gun. You could realistically leave the hole open, I like the idea of the tank being sealed if you still have it on casters and move it. It really doesn’t take more than 2-3psi to move the water out of the tank into the pan. Put a piece of plate over the drain hole as a deflector and I can fill mine in under 30 seconds. The tank obviously swells a little, but it’s 1/8”, I’m not worried about it.
Quite a few pics in my thread, even a video