To be honest, I did not know what HTC meant and forgot to ask. I could powder coat them but not sure I understand what then point would be. If they drop out @.502 I will need to size them down to .501 or maybe .500, THEN paper patch back to groove diameter..unless there is something I am missing. This is new to me.
Depends on what your final diameter is needed. In my case, I wanted to get to .595" from .577" and paper alone wasn't gonna get me there, hence the powder coating. If I understand you correctly, you need to get from .501 to .513 and I doubt paper only will get you there.
YMMV!