Eventually I will be getting around to doing the rear disc convert. Winter and truck suspension projects put a stop on the Camaro. Now I'm back to getting the other parts selected and bought. Need advise/opinions on combo valves again.

Basically, this one with no adjustability, but is the easiest to install
1979-81 Pontiac Trans Am Front Disc/Rear Disc Proportioning Valve at Carolina Classic Trucks
or
This, which is adjustable, but, requires completely replumbing the system for something that, once adjusted will never be adjusted again.
SSBC:: A0730

Comments please.