i have a gfb bleed also. easy toinstall, comes with eveything you need from memory
stock gauge reads fine (despite what others might say), its just herd to interpret...
it reads in mmHg, and the conversion is: 760mmHG = 14.3psi
so taking that into consideration, + 3.5 (or half way on the gauge) is about 7psi and +7 (or full gauge) is about 14psi
hope that helps
cheers,
Warren.
PS more info can be found in a search...