Matt,
I've not fished Rodrigues but have fished with Jason and Mady in Tanzania.
Latham Island is a sand atoll about 100km off the coast and although local boats go out there I'm not sure I'd like to be on one of them! In any case even if you could get one I don't think they'd understand sportsfishing. Mafia Island, further to the south is more accessible but again a local boat is probably not an alternative either.
There's a couple of operators in Sudan who use local boats, I've not tried them but have read good reports.
Early November is a pretty good time to fish Southern Oman or Musandam as well.
Regards,
Trev