Good point on the air bleeds. I will not drill any of my existing pieces.

I have seen members on board say that buying a sensor for each side is stupid, dumb, waste of money, etc.. But I know first hand that "on my motor", there is a difference from side to side.
When I have the car in N and I am balancing out the metering screws, I can move the drivers side main metering screw and watch the P side O/2 gauge move. I have a dual plane intake, so that makes sense. So I have to take my time and go side to side to get the result that I am after for both sides. When I added the second sensor, the cruise was real close side to side and the WOT was off by .5/.6 side to side. Now I have the idle, cruise, and the WOT within .2 side to side.

I would suggest that you move the sensor to the other side to check your thoughts. You may be correct.

I separated my exhaust (straight thru each side) so that I could run the dual sensors without the exhaust contaminating the other sensor. I am glad that I did because I can set here at my keyboard and smile when I see someone say that the second sensor is worthless, especially on a dual plane intake.