Brent is right, you can't eliminate backfiring w/ safc. Beyond that, you should not blindly adjust the afc, you need to utilize a wideband oxygen sensor, and your tuning should only apply to the high throttle settings. I don't recall Stillwater having any dynos nearby, so you'll most likely have to hit Tulsa or OKC. You WILL damage your engine w/ settings that cause you to be too lean, and you can't tell you're too lean w/o a wideband O2. (IOW, don't fiddle with it unless you can see your results)
Assuming you're running stock or lex AFM, you shouldn't adjust low throttle/idle settings via afc at all. If you have a stumble at idle, you're looking at a problem that needs to be fixed BEFORE you start tuning.
...on an unrelated note, do the domestic guys still gather at the car wash by Hall of Fame & Main?