Cricket mini .22 recommended reg pressure for accuracy and efficiency 18.1 jsb

[yukonsmith]

I am talking my first tuning and bumping into walls.   This gun has a Huma reg and a power plenum.   My concern is establishing a good stating point for reg pressure and perhaps a range I should try and stay within.   I do not have a reg tester so each change requires empty and refill to test on the chrono. 
My first goal is best accuracy out to 80 yards so fps is not a driving issue.   The gun is set at 140 bar now and 50 yard groups are 3/4 " and up to many wanderers.  ES is in the mid teens..   Looking for much better ES and SD.    Your input is appreciated.   Nick