Hi Mike
I had a Grayson until about 4 years ago, it served me well, the change wheels were 20 DP same as Myford, but held with a 1/16″ dia pin instead of a key, the crosslide thread was very worn so I bored out what was left of the old thread and adapted a Myford crosslide nut which is still working OK , I sold the Lathe to a friend and he was quite happy with it,
Hope this might be of help to you
Regards