I'm once again upgrading the brakes on my Omni GLH Turbo. I did have a complete braking system from my Shelby Lancer, including the rear disc setup and proportioning valve. I'm now upgrading to SLH III, which consists of Caravan front brakes and 11" vented rears from a '91 GTC. Should I use the prop valve from the '91 GTC or stick with the prop valve from the SL?