Not an easy build for sure but if you endeavor I highly recommend to go the v726 route. The v726 has the correct beat rate and you will not need to glue any subdial hand onto the dial, which I would never recommend for high end builds. Afaik the v23 is not much cheaper than a v726 with a bit of luck. Best will be to search for a donor watch, as naked v72 usually sell for quite a premium over full watches.
Stem you will need one that fits the rolex crown, phong sells them and probably the easiest way to get them.
Good luck!