Hi Simon,
I have done quite a lot of fishing in the Carribean - The Keys, Mexico, Belize, Honduras and Nicaragua. It is quite a different game than any gt-popping and I think you aim a bit high with 150 grams. Jacks, barracudas, snappers and even the odd tarpon are very manageable on a decent pike rod from Denmark and I would suggest lures of a maximum 80-100 grams. Barracuda ARE a lot of fun in shallow water, but you can let them run and jump. A 5000-8000 size reel (shimano sizes) with 50-65 lbs braid and a decent 8 fot spinning rod that casts around 100 grams would be great. I would even suggest bringing a lighter rod still. Most of my fishing in those waters has been on fly and you very rarely need to stop fish from running. I have seen big cuberas in Belize, even in deeper holes on flats, and they would be the only exception when bigger lures and heavier rods would be useful. A lot of the time skipping lures are extremely effective for jacks and barracuda. On the flats and from shore I have experienced that bigger lures and poppers actually can spook fish.
/jonas