If you must do it that way, then I recommend a dealer in Florida because Florida is an export hub to the Carribean, and they will be familiar with the basic laws pertaining to export of firearms. Start in Miami, open the phone book, and go to the shops with the biggest advertisements.
However, I would do it differently.
Most of the problems you are likely to encounter will be in the destination country. There is a very broad spectrum of possibilities. My recommendation is to first decide where you want to live, then find out how you can import from the U.S. Citizenship may be an issue.
As far as buying guns is concerned, there are many to choose from and if your interests are specialized, you may not find the gun you are looking for at any gun shop you visit. This particularly applies to competition target arms. These are often special-order items because they are expensive, the market is limited, and grip size often needs to be based on the size of the customer's hand. Another possibility is to just buy the guns in your new country.
You may not yet fully appreciate the number of gun dealers in the U.S. It's a very large country, and there are many gun dealers. It is an industry not known for scandal, and honesty is not much of a problem. Open the phone book, then go to the shops with the biggest advertisements. They will let you handle the guns you'd like to handle.
