I finally did a retrofit with Centroid Acorn. It is much better than Mach3/Mach4. I recommend it to you. I didn't make the wiring diagram but I can supply pictures. It's much easier than it looks. However, I didn't use the original drive of the spindle.
There's a forum at Centroid and you can get alot of help too, see the post I made there here:
https://www.centroidcncforum.com/viewtopic.php?p=48269#p48269