Dual Plane vs Single Plane Manifold with TBI

I've run my fitech on both a single plane (victor 340) and a dual plane (rpm airgap) - no major changes in part-throttle driveability.
I did notice my spark plugs are more consistent, cylinder-to-cylinder, with the victor. The cylinder-to-cylinder difference on the airgap was pretty minor though.

FAST RECOMMENDS A SINGLE PLANE FOR BEST PERF. .