[solidaxel]

I am convinced that 46 Chevy brakes are "possed"

I had the most trouble with the one I built
Three M/C later and two boosters later it now feels like it will slide the tires and I can feel the power master.
I am almost sure the fix was a 15/16" master #3
I did change the Welwood pads to a much softer compound, and they are very "dirty"
I did read somewhere where the larger thru the frame fittings were a problem and as I remember I think the fix was to place a "filler wire" in the cavity of the frame part of the fitting to reduce the volume..............old age has set in!
Your idea sounds like it should work.
Have you tried to isolate the front from the rear
Get 1/2 working at a time?