My experience is with Pacific sails, but the techniques will be the same. Get, or tie some Billfish poppers. The Sigler Big Game flies are real popular for pacific sails, but they are expensive. Mid Twenties without hooks
Also carry some billfish streamers, and if you have a good captain you trust, if he says streamer instead of popper... Listen. Also I was shown a pretty cool trick a couple years ago. The cap of a 20 ounce bottle of soda with a hole poked in the center makes a very good improvised popper head for any streamer. No floatation, but you can get some good action out of it long enough to move a lit up fish.
If you are teasing the fish up, make sure the captain knows you don't care about IGFA rules, and that he doesn't need to drop into neutral before you cast. The fish will be much more likely to chase your popper if the props are spinning. Some captains assume all fly fishers want to be coasting for the cast. Also discuss with him and the mate what they will do when the fish is hooked, or when you get it near the boat. This should happen BEFORE you hook a fish. If they're going to start backing down on a fish, you don't want it to be a surprise to you!
It's really simple once the fish comes up. Using a very dense line (depthcharge, Rio Deep Sea, etc.) just drop (flop, plop... We ain't talking gorgeous casting technique here) the popper in the vicinity of the teaser, and keep an eye on that teaser as it's jerked into the boat... they hurt if they hit you! The cast won't be long, usually under 40 feet. After that it really is a matter of whether or not the fish gets the popper in its mouth. Sometimes they do, sometimes they try but fail, and sometimes they just bill it around and never eat. It's not your fault or the mates if it assaults your popper with no intent to eat. It just happens.
Lastly, use as long a shock leader as you can manage. Your chances of an intentional release are much better with a long shock. 4 feet is a great length if you don't care about the IGFA, as long as you can cast it. Yes that means you better find some water where you can cast your rig, including the flies, and practice at least once a week before you go. You don't want your casting to be the thing that kills your chances. Remember if you are fishing from a cruiser, you will be sidearming your backcast from the port corner of the boat (if you are right handed), and it's a good idea to practice watching your backcast, then snapping your head around to pick up the teaser. That means when you practice you need to cast at targets with same approach. There's lots of crap to catch your backcast if you arent' careful on a cruiser.
Find out what else is swimming around during the season you will be there that might come in on your teasers. Having a rod set up for another species can turn a day where you mostly sit on your hands into a day where you catch fish while you're waiting for the sails.
Your local library may have Trey Combs' Bluewater book. Don't let all the talk of "I need to know that my leader will part just before the rod breaks", and "you have to break a half dozen rods before you know how much pressure you can put on" bother you. He's relatively full of it, but the techniques listed are quite good. It's just fishing. Big, powerful fish, but just fishing. It's supposed to be fun.