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I guess at this point my biggest question is 10-11:1 air fuel ratio still too rich? I cleaned off the O2 sensor. It is very responsive and seems to work properly. Should I trust it? If so might I still damage the engine?

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That is way to rich, it will foul plugs and can damage the cylinder walls. Check your manifold vacume in gear and then check the power valve rating, report back It sounds like the power valve is opening at cruise RPM, maybe not While you have the center carb off and apart look at the main jets and tell us the size on them also I've used, tuned and successfully race a six pak for 5 yrs, street motor on pump gas, 10.34 ET at 128.6 MPH cork up on pump gas in a 3450 lb Duster on street legal M/T Radials I made mine idle at or above 14.8 AFR and drive at between 13.8 to 14.9 AFR at light throttle with the power valve closed at or above 2000 RPM to 3000 RPM I have now(this year) switch heads to a set of Indy SR M.W. port size with a Indy 400-3 intake and 1050 Holley Dominator carb, I have it set up to idle at 14.8 to 16.1 and drive at low RPM, below 2000 RPM, around 15.0 and above, I'm still working on it so it may end up a tiny bit richer than it is right now as it does have a lean stumble coming off the idle circuit,especailly when cold not good Carbs are harder to tune than EFI, you got to take them apart to work on them and make changes