Thanks for the input. Just one sensor per tank. My main objective was to know ( with certainty) what is left near empty. Since Vans senders yield varying results, I installed Aircraft Extras low level sensors in my -3, and the no alcohol MoGas ate the sensors and they leak.
So, for my -4 project, I said ENOUGH !, and ordered CIES based on their reputation . One option is to use fuel lube on the rubber, but Proseal only (no rubber) is the proven path.
RV-3B flying w/7:1 0320 / carb / Pmags / Catto 3b / digital steam
RV-4 fastback w/ Superior roller 360/AFP/G3X/CPI/Catto3b