I decided to update this thread, partly to get everything in one place, and partly to avoid burdening other threads with absurd levels of detail on restoring strops that were probably not worth bothering with by any 'reasonable' metric...
So, with respect to progress on the second of the strops in the opening post above, the convex paddle strop, this was discussed in this thread:
https://sharprazorpalace.com/strops/...strop-why.html
This one is waiting for a decision on what to paste the two sides with.