I may go with your suggestion Okapi and put a lining in the cup for the bearing with my next one as I want to explore tempering at some point for a hobbing project down the road. I aspire to make tooling of Stefan Gotswinter calibre one day, but I'm still cutting my teeth as a noobie engineer/machinist, so keeping things to an attainable level to start with
Right now I'm currently working out my setup to drill the four concentric holes in the cup. My mill is still not up and running yet (waiting on a reamer) so will be using my lathe again.
The cross slide doesn't have enough travel to hold the broach shaft in a jacobs chuck, even the 4 jaw makes the cross slide overhang too far, so I've ordered a 12mm 2MT collet in order to bring the cup in close enough to work on.