Right, flushed is when the screw is level with the metal cover on the regulator. I think stock is two full turns in from flush on the LPR no? You shouldn't need more than that unless you're trying to shoot really fast.
As for the "kick" every 4th shot, I have no idea why that would happen. Put the gun on a chrony and see if the regulator may be acting up.
ETEK 3LT, with 14" Ti boomstick and cure 3 + bolt F/S
Vanguard creed eyes, membrane, bolt pin, detents, gaskets, schraders, orings and more F/s[/color]
Old school angel poppets/cup seals(LCD and A4/speed), spring detents(not sure which models) F/S