hi dave. i was there in august too, as marty kindly acknowledged, and that week the 'squitos were fierce. i hope they are better for you.
anyway, here's my recommendations:
someone i met there also brought "cutter" repellent, which is very weak but has other stuff too, and mixed her 100% with that in the pump spray. she said it worked. (however, she was soooo happy to borrow my benedryl cream). tha brings us to Benedryl cream. it is a godsend, especially when used with "AfterBite". use the benedryl cream, not oral, because the oral will make you drowsy, esp if drinking.
i also like to bring 10 1-gallon size ziploks, they are great for everything from wet suits the last day to bringing home the rum & Marie Sharp's hot sauce. mine leaked and i was very glad for the bags. used them for seashells too. bring neosporen too, and waterproof band aids. frank and another guy both got foot blisters from their fins when diving so much. these really helped. if you want to tan, bring SPF 8, but always wear some sunscreen. i bring SPF 45 and 15 also for noses, backs, etc. and dont forget your big, pretty smile!