Tuna Lower Keys

I'm heading down the the lower keys in early September. Mainly lobstering, reef fishing, but if its calm, I'd like to run off the reef a little ways. Is it possible to catch Blackfins just off the reef in 200ish feet of water? If so whats the best method?

If I can find Pilchards, I'll load my livewell with them, find some weeds or debris, and throw out some live chum. Otherwise I'm open to trolling. I need pretty good conditions to make it out there comfortably so it may not happen, but I've never caught a tuna and really would like to give it a try.