LTFT and PE Adjustment

[nsmcc]

I have a 99 corvette with cone filter, cat back, and predator tune. The predator is U7198 with 2.13 on it. I have a OBD II program that i can log with. My predator can't record. My original LTFTs on a log would fluctuate between +7 to +15. I adjusted the slope by -8 and did a check of LTFT and at 70mph in 6th gear1830rpm they were at about +3 but at 55mph in 5th gear at 2000rpm they were at -1.6, and at idle they are at -10.

Question that i have is LTFT at idle of -10 good, bad, or doesn't matter?
Does the gear that is used make a difference even if the rpm is close?

Additional question that i have is regarding PE adjusting. I read on 06MonteSS's sticky that you adjust the PE by half of the LTFT value. So my understanding is that if i adjusted my LTFT by -8 that i should adjust my PE by -4? Also, my car does not have the ability to read AFR.

I appreciate the response. Thanks

[Wireman134]

I also have a Series 2 v2.12 Predator. I use a MAFT set at 5%-10% rich to do most of my adjustment across the board. My idle LTFT's are -10.94 with slope adjusted to -1%, at cruise 1900 rpm LTFT's at 0% to -1.56%. Reading O2 milivolts around 900mv is close to 12.8:1 AFR. AFR readings from Predator use the narrow band O2 senors and are not as accurate as wide band readings. It will be just a ballpark figure.