Another update on this whole meter contacts saga: it just so happens that I managed to score something like a Fluke 87 III off our usual sometimes-a-bargain trading site.
The meter is sick and needs some TLC but, while troubleshooting, I noticed that the rotary contacts, although having a different physical layout, they looked as wide as the slots for the contacts on my 89 IV.
Hmmmm....
So, I took these contacts from the 87 III and installed them in the 89 IV and, what do you know, it worked!!!
I now need to source 3 x contacts for the Fluke 87 III, but I am hoping I'll have better luck than with the ones for the 89 IV.
Anyone happening to have such contacts as spare, by any chance?