the water trap should go between the compressor & the airbrush, so it will work w/ any brush.
i use a regulator / moisture trap combo plumbed w/ a quick connect directly to the compressor. then the line out goes to the brush.
moisture traps are actually more effective further down the line as it gives the moisture in the air more time to condense. i have also seen tips in FSM about running a coil of airhouse in a bucket of cold water between the compressor and the trap to really wring the water out. but it looked like a pain in the butt, and i don't get moisture problems.
Badger makes a combo piece like the one that i use that costs abt $65 retail and maybe $50 online. all i can say is save up and buy one, it's worth it!
ed.