As fond as you are of the vintage AT, there are far better cartridges out there, even among the MM ranks.

As to belts, I have a supply of Rega belts that I laid in when I was still a Rega dealer, so you're covered.

A bit off topic: You should try a trio of iso-bearings under your table. Repeated tests in my shop and at a couple New England Bottlehead meetings confirm that it's the next best thing short of a suspension. Firmer, more extended bass, more coherent, less strident everything else . . . . If you try it, stay with aluminum bearings. Steel and other extremely hard metals take on a nasty hard edge.