So far, I have always used "live weather" when flying MP, with the assumption that that was what everyone else was using, and so you'd all get the same weather conditions. This is particularly important when flying at ATC sessions, because when ATC gives you a wind check, you want that to match your actual flying conditions (e.g., it sucks to get a wind check from ATC that doesn't match your own weather settings).
However, now that the hardcoded non-TLS URL for live METARs no longer works, you need to run a patched FG release, or an unreleased development version, to use live weather, which I believe isn't something everyone out there is currently doing. Personally, I have patched FG; since I'm running my own build anyway, this was a small effort, but I understand that it'd be a daunting task for a non-technical user.
So what's the current convention? Should I be using live weather on MP? Or should I switch to, idk, "fair weather", and wait for the next FG release? Or is this something that gets decided per MP event, in which case I think it'd be nice to somehow advertise the recommended setting somewhere?