If you learn to install and remove grips with compressed air, then that part is taken care of.
I've put temporary extensions in. Wrap the insert portion in masking tape so it's good and tight, and wrap the "finished" shaft tightly too. Then blow the grip onto it.
Also, check this out:
You have to get the head threaded. And the gizmo costs $50 retail. But once you have that setup, you can change shafts in a few seconds. You'd have to go through a clubmaker with a Wishon account to get it.