Could it be that the thickness of the proseal after removing the supplied gasket is a critical measurement. I made sure I had a flange seal thickness that was reasonably generous. Didn't have issues with rib interference.
Any tips on fitting the fuel senders on the QB wings? I thought it would be as easy as bending the rods appropriately and plugging them in but you have to tweak to fit, problem is, can't see anything really to tweak and my bore-scope won't fit through the holes.