initial findings...

[Idaho Sharpshooter]

never mind...

[noisewaterphd]

Unequal thickness may squeeze to out of round Pb and give instability problems.

I am currently a believer in that statement.

What I have been doing for rifle cartridges is to size appropriately first, clean in laquer thinner, then PC. Much the same as you have described.

In my testing it has helped a bit.

[Bama]

MY experience indicates that the sizing before and after does give a more uniform coating thickness. If I remember anything about the equations it could only effect the out of balance by the difference in density of coating vs alloy and the volume displacement difference. Sizing before PCing should reduce the volume displacement effect.