best AFR for Power??

My af gauge is a great tuning instrument, but what my plugs are saying is what I make my ultimate decision off of..
A chassis dyno would be great but it would likely just be perfect for the weather that day... I've lost a half a second at the track because of bad air..
Ultimately you're going to have to do more test in tune and watch the weather as well to get down to the last 16th of a horsepower... For that day and that air..