Just been out and measured some 44-40 bullets uncoated and sized v coated unsized.
Uncoated sized .4291".
Coated unsized .4318".
Total size increase from a light powder coat is an increase in diameter of .0027" , 2.7 thousanths of an inch or 68.58 microns.
I have tried the wet coating method using Acetone and powder , What a mess that was and when baked it looked like it had been applied by spitting it on.