So they have arrived and so far it’s possibly a good solution, though not great. I needed to clean some plastic residue out of the o-ring channel. The fit on the schnozzle end is great. On the Thermarest end it is just ok. Â I got the pad inflated well enough, though it’s not a seal that inspires a lot of confidence.
it could be as easy as finding a chunkier o-ring. Which I will try to do next.
I would post a pic or two but it looks exactly the same as it does on the link.