I was saving this for test 2 which was supposed to happen last Fri - and didn't.
The question we wanted to resolve was what front wheel to use for a 13 mile out and back TT with likely side-winds with the turn-around 300ft higher than the start. This is the VOS TT. We are testing light 50mm profile 25mm wide vs. 90mm profile 22mm wide 250g heavier front wheels.

So we are 4 runs into an 8 run series - this was the side tail-wind test.
I did calculate based on no side-to-side movement, not tire friction differences that the more aero wheel would be faster. I'm not so into calculations when a test can be done.
For a long time I've noticed that the side to side/and handling of the bike is an impact that is not measured in a lab wind tunnel - because its hard, and hard to calculate too.

While not conclusive - I think it was conclusive that it is far from obvious which is better with a side tailwind. More testing to do.

Details:
Pressure was about what we would run for the TT - 130psi on the 23s 90mm and 120PSI on the 24s 50mm
Power was held to average 225W - rider did not see HR or speed.
Wind on the last two tests was about the same, about 6-9mph 45degrees off riders right rear - tail side-wind
Speed was 3-4 mph slower than real TT speed on this bike (maybe)