Link to wiki page:
Increase tire pressure to max sidewall - EcoModder
I went back though my MPG spread sheet and revised my data. It turns out I also got new tires so I had to toss out the old data. I can say that they gave me a 1/2 MPG gain (1.5%) for sure, it might have been more. Different tires had different results. the numbers here are for my current tires.
ABA testing would be tricky, tire temp would make a big difference on the results. So warm up car and drive train (tires to) and do A runs. Change pressure and let tires cool off (2 or more hours), re warm up car and tires (same # of miles as first time) do B runs. Repeat for A2. Hope like crazy the winds stay steady over the course of the test runs.