Cox put some effort into arriving at 4.5 x 2 as a well matched load for the .020..so deviating from that with more pitch means that the load factor needs to remain close to what COX arrived at for a good match to the engine.
I think removing micrograms of weight from inside the piston is a good first move to enable the engine to respond the most to slight reductions in load. I would practice first on SureStarts to get the feel for it.