Why not just get a couple of old American style balltops rather than trying to build your own. The NOS stock seems to have dried up but you can still find them used.
True, but I got a good deal on a sticks/buttons kit, plus I like making stuff myself - it's a big part of the fun for me.
It also means that I have a huge choice of balltops (standard thread) which I can change simply by unscrewing them.
This will make changing my CP color scheme easy if I choose to down the road.
I should probably have mentioned above that I have a metal lathe, lest I give people the incorrect impression that you can just 'lego' these parts together.
I was half expecting to have to make custom shafts from scratch, but I removed the plastic parts from the existing shafts today and it looks like they will be usable.
I just have to wait for my balls to arrive (giggity) so I can figure out what spec the threads are.
I think they are 6mm, but I don't yet know the pitch or what the length of the stud needs to be (giggity).