Proportioning valve/Roll Control

[mrtimstik]

I have a few questions about the braking system on my car at the track. What is the correct reason for having a brake proportioning valve on the car? At the track, do I(Number 1)crank the rears closed(no fluid pressure to these), do my smoky burn-out and then my run? This concerns me because I will only have front brakes at the end of the track when I believe stopping is far more important then going. Or, do I(Number 2) adjust this valve to allow the front disc brakes to have slightly more grab than the backs(a how-to needed here) and use a button activated, "Roll Control" to lock my fronts for the burn-out and maybe launch? I am confused and welcome any comment that will help me have fun with my car. Thank you very much folks. Tom