[Bitza]

Hi all, I've got JPDiag on my laptop that I've never really used apart from resetting the TPS, but I would now like to use it to adjust the fuel trim. I'm guessing that the smaller the number the leaner it will run, and have no idea what a significant adjustment would be, like the equivalent to 2 clicks on suspension. Can anyone give me a few pointers?
Background:- I have the choice of two different fuel feed configurations that I can fit to my heap the original return system where the smaller throttle opening tend to be fine but a bit lean at larger opening, and I also have a direct feed system that basically seems to give a slightly higher working pressure, so not so great at small openings (a bit rich) with the odd pop of excess fuel burning in the exhaust on the over-run, but better at larger openings. Obviously I run the direct system so would like to trim the fuel back a bit (leaner), long term I'm planning on a remap of the ECU.