Why not use these? http://www.pressuretek.com/bustcopl.html
I haven't test run these yet, but for $6 a set, I'm not complaining. The 3/8" NPT requires a 1/2" MNPT to 3/8" FPNT bushing to fit all my valves, but does not restrict the flow as the inside dia. is still wider than the inside of the...