Well I can help you narrow this down pretty simply…
99% of the time you will be shallow water sight fishing for reds, therefore you can eliminate any intermediate, or sink tip lines for reds…
our water is pretty off color for most of the year, and reds aren’t all that spooky most of the time, so no need to spring for a fancy clear tip line.
With redfish flies usually being on the bulky side of things, i like a Weight forward, floating line, preferably with a short head… To make things simple manufacturers all make “Redfish” lines which usually all fall into the specifications I just mentioned.
SA and Rio make the two best in my opinion… the coatings on Rio lines just don’t seem to hold up as well, though I do like the taper on their redfish line a little better…
Either one of those lines should give you multiple years of good service if you care for them properly, and avoid casting your line over oysters…
One more elephant in the room that you’ll need to adress sooner rather than later is that battenkill reel.
No you don’t need a $600 reel to catch reds, and no it doesn’t need to have a top of the line drag system… but that reel you have uses an exposed gear tension drag, and a cast aluminum frame. Salt water will destroy that reel pretty quick… It will be fine for a bit, but its gonna get eaten up, and probably faster than you think… So if I were you I would be saving up for a new reel… there are plenty of options in the sub $200 dollar range that will be just fine… Look for machined aluminum frame, and some form of stainless, sealed drag system… Lamson Reels would be a good place to start…
Anyway, don’t make this anymore complicated than it needs be. Go to a fly-shop (Charleston Angler, Lowcountry Fly Shop, etc…) Buy one that says “WF-9-F Redfish” (assuming your rod is a 9wt) and go fishing… Rinse your line off every trip, and twice a year use a good commercial fly line dressing to completely clean and re-dress your fly-line, and it will last you a long time. Don’t