I don't understand what you mean by "air fin". Please try to explain in a different way.
I got a pair of Solex 35s to run like a clock on a tube-frame sand rail. Pull the fuel line from one carb, and install some hose and a "T" to the gauge. You'll get the pressure across both carbs. Stan is correct that the float valves are usually not that great quality. But if you make sure you're at no more than 1.5 psi you should be OK.