Anybody ever tried this little gizmo?

92b,
I never said distribution was perfect, & therefore the plate would change that. I merely said distribution would be affected......[ Post #41 ]. Whether the way the plate changes the distribution, & the engine makes more...or less...HP would be hard to say.
There is another explanation, other than distribution changes, for the plate requiring less pump shot & curing a flat spot. It takes up area, which will increase the air speed; that should improve carb signal &/or atomisation, in effect making the carb look smaller to the engine.