I know a few operations that will run tech trips. Again, I am sure you may know people that have access to helium, but I don't think any shop in this general area advertises that capability.
There is one SHOP in Destin that has Helium. I don't think they bank it, as there is insufficient call for it, but they can fill you. One of the guys there is an Ozark fanatic, in fact
Heliar is easy for just about anyone, of course. True Trimix is a bit more difficult due to the booster requirement. With Heliair you still need a booster to keep from sending back a LOT of Helium, but you can then "get smart", put in a storage bottle, and decant from the supply to the storage and that solves a LOT of problems, including making turnaround on the Helium bottles easy.
You're right on the Ozark - I grabbed my GPS Utility and did a quick "span" from the pass to the marks I have for it. Roughly 30nm out from the Destin pass. Its in DEEP water
The ~50' of clearance is just plain smart. Less and you risk having the wreck tampered with during storms. They used to let people sink things with less relief, and the result is that we have several wrecks in shallower water with the superstructures ripped off or the wreck itself basically gone.