GT,
You may want to re-think the flats fishing and opt for the Sailfish off shore. If there is any wind, the flats fishing will turn into a boat ride. This time of year is best for Sailfish and Kingfish (Mackrel) offshore.
We go down to the keys for the diving and offshore fishing but we skip the Sailfish, been there done that. Stuart is the Sailfish capital of Florida, they just get in the way most of the time while we are after Wahoo.
We usually fish the deep reefs (1000+feet) with electric reels for Tile fish, Snowy grouper and snapper. If the charter offers "deep drop fishing" you may want to try that, you'll have some great eating fish.
Robert