Great write up hippo, this gives me memories of when I had my first upo 45 when I came to Rwg a year ago, I had the same problems as you, threads knackered on arrival and keyless issues, also removed my case back to find only 2 movement clamp screws
Its definitely nerve racking removing the old tube, best mod I done was fitting a genuine omega crown and tube, feels so much nicer
If you need any help buddy give me a shout.
Great work mate