Funny you mention No-Ox-Id - there’s a jar or two on their way here as well! Looking forward to seeing the results, my little tiny bit of track currently shares the room with a kitchen renovation workshop.
There are a huge number of threads on couplings out there on other forum pages - if leaders fail you might like to look at the Burford Autocoupling or the Flippem coupling, both of which claim to be good at coupling on curves. I have some Flippem bits spare if you want to try them.