I have been using there this technic:
boating for hours in the blue water at 20/ 30 miles off the coast and looking for upwelling currents (cold).
Then do following slowly this current until we spot something drifting (a log, a dead turtle..)
I check the baitfish close to the thing. If small bonito/ skipjack swimming at about 40feet depth: this is the best hunting conditions
then I play the flasher (or rarely chum )waiting for my turn.
Dorado use to visit the spot in small group or alone (female) and wahoo...
Marlin visit is possible.