I have your basically the same fuel setup in my rally car, except i still have the standard mechanical fuel pump and i have no issues at all, except i have a slight mod to my carbs. I have a vent in the top plate that goes to a small filter and also have foam filled the top area above the floats to stop fuel spilling into the top of the jets.
On the offroad buggy, we use to add a small tube to the top of the jets and basically make a small raiser to the the little cover so that fuel couldnt spill into the jets.
Found that once fuel spilt down the tops, it would start spluttering, so this could be your problem.