A 7 mil will be fine as well. Its whatever you think you will be most comfortable in. There is no such thing as overkill when it comes to comfort while diving. If you are only going to be diving the Tampa area then I have three recommendations for you. Get with Capt. Ty here on the Board and see if he has any openings on a trip out of St. Pete. He is by far the most highly recommended Capt. in the area. If he is all booked up there are some other charters you can go with. I also recommend trying to hit the Sapnish Rocks in Bradenton. Its a shore dive right off of the beach and it is a great dive. Last but not least take a ride about an hour and a half north and dive Paradise Springs. This one is my favorite spring. It is an overhead environment though so before you go you need to be certified, experienced and comfortable with an overhead. If you are then it is a great dive.