I guess the idea of monitoring both banks stem from when I used to run a Six pack and the outboard carbs required stagered jetting but now I'm running a 750 holley on an M1 single plane so the jetting should be the same side to side. I will probobly do as your doing Y07 install a bung on both sides, tune to one, then swap the sensor to see if there is any diff. I've heard of guys installing two sensors with a switch to one gauge but as you stated the unpowered sensor may foul out.
