Recommended Brand of Valves

Yep, i would consider using an 11/32 stem valve ... you could cut a 1.94 down to 1.78 and probably find a 1.55 or just cut a 1.60 to 1.50 if you want...
The price for your machinist to do it "cut diameter down" ..though it might negate the cheap part...but maybe they're cool and will do it for a 18 pack pizza.