I don't know anything about a Provari, so can't be much help there, but I do know about the subtank nano, I use them every day almost, the only time they leak on me is when I leave them in a hot car. Other than the hot car thing, my nano tanks don't leak. I use a 30PG/70VG mix so that might be why they don't leak, maybe with a thinner juice they might leak.