they do great, but I struggle to get even close to the numbers they get.
I generally fish an 8wt, but if the wind is down I will use my 6wt, usinf an Orvis Depth Charger line to get me down in the 15ft of water we fish. and the standard flies like clousers etc, plus some strange articulated clousers I tied up with those curly flytails in the rear hook to try and mimic the jigs they use.
Mud, I've never fished the gulf, but these remarks you've made IMO tells the story. First, I don't know how you expect to compete on numbers with the other gear guys or why you want to. They can cast & retrieve, and get their lures down much faster than you can, so they have the advantage in that regard. Even with a fast sinking line you still have to wait for the fly to get down to the same levels those other guys can get their lures.
Perhaps, in your desire to "compete" you're not concentrating on how to effectively fish your flies. To me, that would be the first consideration to change your success rate. Use what you've got to the utmost.
You didn't say how long your leaders/tippets are, but to get a fly down faster with sinking lines you generally have to go shorter, like 3' to 5' total. A straight leader/tippet is all you need for this. However, you have to take into consideration the possibility of spooking fish with the line if the waters clear. I would still start with the shorter section & go longer if necessary. But, if you do have to go longer, you have to also understand the flies going to take longer to sink. Add some current & that too complicates the situation.
All fishing methods have pros & cons & it's not always a fair comparison when doing so across the different methods. I know I can usually catch more fish on spinning or casting tackle than I can fly tackle, but I still enjoy using the fly tackle the most. Doesn't mean I can "compete" with others using other gear & I don't even try. I'm not fly fishing for that reason.
Perhaps you might consider the same.
Otherwise, it sounds like you have the proper gear for what you're doing.
The only other consideration I can think of is the size of the flies compared to what the other guys are using with lures. If they're having success with 4" lures for example, you may want to have flies of similar size & profile. IMO, it would not make good sense to be out there tossing flies that are considerably different in size in a case like that.
Of course the fish always tell us what they want, so have a variety & IMO the wider the variety you have in size the better your chances of having what they may want. That goes for sink rate too. All jig sizes don't sink at the same rate.