one screw to start the alcky(turn on psi) the other screw for when you want the "full" 100% pressure(max psi). Mines set at 5 psi (turn on) and 15 psi max. I run 24 -25 psi and a lubrant 26 deg chip. Maybe 1.0 KR , but it's gone by 3rd gear. HTH.
Ross