Finished pulling the mold last night. It didn't want to release, and took some small bits of the plug with it.
Apparently I didn't get enough wax, or PVA, or something. The bits that came off the plug are all either primer, or Spackle, so I can remove them pretty easily.
I'll be extending the parting flange so that I can vacuum bag the final parts. All things considered, it's not that bat for my first full sized mold.