I have the same marker, sweet spotting with the check it springs sweet spots around 340 FPS. Turn your IVG 1-1/2 to 2 turns from flush, and then increase the reg pressure from zero to it hits your field limit. Fine tune with the IVG. Your reg output pressure will be between 250-300 psi of I remember correctly. I think I called check-it/paintball gateway to see what they set the reg at, they said 325 psi I think.