Cool tip with the boiling water! I do the same with my arrow inserts but didn't think of trying it with bow nocks.
The shape of your nock is interesting - there's quite a lot of horn there that you don't need and they're very ornate. They look more like Victorian target bow nocks than warbow nocks. If that's what you're going for then it's fine (I actually think for Victorian nocks they're pretty cool!) but it's worth maybe looking at replicas of Mary Rose nocks to get an idea of what most people do.
The guy who makes the absolute best warbow nocks is Dave Pim. I was at a shoot with him on Friday/Saturday (before the great English weather ruined everything...) and some of the nocks on his bows were beautiful (and absolutely tiny!) He only uses just enough to protect the bow tip, no more. You want the tips as light and aerodynamic as possible for the best cast.
Here's his latest article on the EWBS website about making medieval warbow horn nocks.
http://74.209.214.7/~englishw/TudorSidenocks.htmlAnyway, that's not to say yours aren't nice because they are! Your bow looks great and the project is coming along nicely so well done. I'm looking forward to seeing the finished bow!