I don't have a CRT brake, but I have my 2-step wired to my brake button and I have never popped the 5 amp fuse I feed it with.

I would guess when you find out why you blow a 25 amp fuse you'll find your problem. All you should have feeding off the relay is the brake solenoid itself and the 2-step, right? Where are you getting the reverse light signal from? It seems like you have a ground hooked into the wrong place.