Just a quick update: to better test this hotend design I decided I would have to build it into a real 3d printer. Unfortunately I don't have one I can cannibalize, so I had to go buy an extra one. Being cheap I bought an Anycubic Kossel from China for about $180. This should arrive this week and I hope to have time to assemble it over Thanksgiving. Once I have it working I'll switch out their hot end for my version.