Here's a bit of information that I found out about the Dressmaker. Hope this helps you.
https://sewingiscool.com/dressmaker-...achine-models/
Also, not long ago I ran across this man's site. His name is Michael Anderson and his shop is in New Hampshire & has been in business since 2001. From what I can tell, he's very knowledgable in all things dealing with sewing machines.
https://www.facebook.com/wolfegangscollectibles/