Not sure what kind of fuel you are seeing but OL AFR 12.6:1 seems to work well maybe a little richer say 12.3, where I have mine. My car is 07 Z06 and made a bit more horsepower as high as 13:1. I just do not go there on the street or anytime for that matter.
Use B8101 for modifying VE table.
Use B3618 for wide open (OL) tuning.
Use B5101 (High Octane Table) for setting timing.
I have a couple of tunes for 07 LS7 with headers/KB II that I can send along if you are willing to send me a copy of your final tune. Let me know.
dchalk@wi.rr.com