Kit received, waiting on bugfixes before assembling. Might need some soldering practice, too....
On a related note, a ten year old chinese knock-off SNES pad seems to have near perfect fit, with three plastic tabs lining up with the three holes on the new PCB perfectly, only the bottom screw mount needing a few microns of dremeling. The plastic is a bit cheap, though, might still want a new case. And the US color schemes on the buttons wont absolutely do. Drab...
Embedding doesn't seem to work for me, so here's a link to a picture.
https://imgur.com/a/H3F3rXh
A proper SNES pad for comparison, likely would not work, and a Honeybee SF-3 for completeness sake. A bit too big.