Yep, simply trial and error... I have had multiple JP guitars set up the same way, same string gauges, with the same amount of springs, and the distance of the spring claw varied a bit on all of them.
Hi!! I think I got the tremolo stabilised now. Not a big deal. BY the way, can one keep the guitar cable plugged-into the Mono jack or the battery is activated when the jack is in, like on guitars with active pickups (EMGs)?