Not sure if I replied to you on this or not. It just kinda "popped up" in my mail tonite.
To answer your questions:
Sorry to hear you are not able to get "fresh" Permatex thread reapir kits.
The Permatex I have used does set up hard. I have no way to test the cured Permatex
in the holes in the board, but the Permatex on the mixing surface gets quite hard, but I'm not usre if it's "rock hard".
I would not worry about the uncured Permatex in the holes.
When you get a fresh batch, the curing agent in the fresh kit should harden and uncured
epoxy down in the holes.
If you want to clean out the holes, just screw an old footstrap screw down into the hole.
Wrap a piece of paper towel around the screw. That should clean it out pretty well.
Use of an oversize screw could work, but where will you get an oversize screw with the
correct "PT" thread geometry?
Hope this helps,