I would run 71/78 nothing wrong with 12.5 WOT. You will find cooler air will lean the AFR a little, as in warm afternoon cool night air. If it cruises good with the 71 leave it alone. If you find in the future you are running lean at WOT in the front cylinders put larger PVCRs in. For example you currently run a .046 PVCR put a .052 in. Air bleeds change the fuel curve, smaller starts fuel flow sooner bigger later.