dt750 boom mounts

A mounting system for 10mm round booms.
Three part modular system consisting of:
"Traditional",
"Counter sunk flavour", and of course
"dt750 replacement mount"

I haven't actually got around to printing these guys yet. Go forth, brave technophiles, and let me know if they work!
Also, if anyone can suggest a reliable way to get them all aligned, (motors all pointing "up") that would be helpful.