VicT,
I haven't fished the Hilton Head/ Beaufort SC area for a couple of years, the Marine Corps moved my away and hasn't let me get back there since.

But from what I've read and heard recently the fishing is still great.
I primarily used a 7-9 wt for all of the inshore stuff. I used my 7wt with a floating line or intermediate and my 8 wt with a sinking line (300 gr) to work the edges and holes. I recommend the floating line if you plan on sight casting up into the spartina. I would go with at least a 10 wt if you want to go after the "Man in the brown suit" - a.k.a. cobia
I haven't ever fished with Capt. Marty, but I have heard great things about him. Here is a link (
http://oregoninlet.us/flyfishing/top...?TOPIC_ID=1225) to a post that Capt Brian Horsley put on his website (Outerbanksflyfishing) concerning Capt Marty and the fishing in the Hilton Head area. Good luck and let us know how you do.
Semper Fly