Bikes with internal pump don't even have a petcock, so I left mine open. Last owner had bought 2 new pet cock's, didn't last long before leaking. Then I had the chance for free to invest . Got the sliimy O ring out, after some filing, correct one in. Discovered different tread lenght on the cocks, making it harder to make sure it woudn't come loose. Make sure all hoses are in order, NOT perfect but no more leaks with a tiny strip of JB w, a little redneck I know.
6mm outlet on the 90 degree adapter, shoud be enough, but why the 90 degree ? I have to check the houseing route tomorrow.
Cheers Tom.