ESQ Screw Down Crown Replacement

Ahoy PMWF mod experts !

After some beginners luck replacing a movement in a Wenger S.A.K., I now have the courage to tackle fixing/modifying a favorite ESQ which has been off the wrist for years waiting to be brought back to life. The movement to replace is a Ronda 315 which are available on the internet. What I need help with is how to replace the stripped threaded tube and crown? How to remove/install the threaded tube. What replacement parts are available and where to get them?

Thanks,

Greg