From another forum:
If you are only going to take one fly line, I would go with an intermediate. I have been down there several times and always fished tarpon intermediate lines. I have friends who fish down there that like a faster sinking shooting head. It is kind of a matter of personal preference and fishing style. I like the intermediate because it can allow the fly to "settle" before the fish is on it and when you pause it, the fly remains neutrally buoyant and doesn't sink (which a real baitfish does). That is if you fish unweighted flies (which I mostly have done for roosters). You can fish weighted flies and many roosters are caught that way, but I have always fished unweighted. An intermediate also allows you to fish very shallow areas which there are a lot of down there. There are many situations where the faster sinking line would be an advantage though such as in drop offs, rough surf and windy conditions. If possible, I would bring both lines. As far as floating, that would be my last choice. There are scenarios where they apply, but I wouldn't bother with it. Realistically you are taking a big risk if you only take one fly line anyway. If it gets cut, stuck on coral, a fish takes you into your backing and it cuts off etc. you can't just stop in the local fly shop....As far as a casting adjustment, the intermediate would be a lot more similar to a floater than the fast sinking shooting head type line. Shooting heads and fast sinkers load very far forward in the line and won't cast if you have too much line out so they take adjusting. Hope this helps. Good luck, and let us know how you do!