Here are some general factors to consider. Yes I own both modern and traditional ML rifles, and traditional shotguns, and I for the past ten years have exclusively hunted with traditional black powder arms.
You want to extend your hunting season. Nothing wrong with that. That's what got me started in black powder hunting. I was in college and by the time I got home for Christmas break (it was
Christmas break back in those days instead of Winter Break today) the only deer season open was black powder, AND if you wanted to participate in that season, you had a caplock or a flintlock since inlines weren't invented yet.
Inlines do look appealing since they resemble modern rifles, but this can be slightly deceiving. Inlines when they come with open sights, the sights are crude so
you will need a scope. An inline like the traditional muzzle loaders will need for you to work up an accurate load. It's a bit more involved than a modern rifle where you can go to the range with a few rounds from different ammo makers and see what shoots well. Plus the cost of the rounds tends to be on par with modern ammunition in many cases.
One common inline mistake is fellows think it's as weather secure as a modern cartridge rifle. They are better than flintlocks, but pretty much on par with traditional caplocks when it comes to rainy, damp situations. Most fellows with an inline use a black powder substitute since they think it burns "cleaner", and some do, but the substitutes also are tougher to ignite and so damp weather causes problems too. AND if you want to shoot any kind of ML, expect a few minutes of a dirty, stinky cleanup. It's not that bad.
Another common mistake (imho) is fellows try to duplicate a modern hunting round with their inline. So you see these folks launching a projectile with somewhere between 100 to 150 grains of powder.
You wrote, "
Pretty sure those guys would have gotten Rem 700's in belted magnums if they had been available." Probably true, but they weren't available and more important for you, don't try to make your inline perform like that. The tech is limited, even if you buy something that looks like a bolt action and is stainless steel. That's the whole point of the extra season, because the tech is limited, it's not simply grabbing a different rifle and harvesting venison. There is more to it.
So..., you're going to need to work up a moderate load, that is very accurate out to 100 yards, and I'd recommend you use a loose powder and a powder measure to do this and forgo the large pellets. This is going to take a little range time and some $ since the projectiles aren't cheap. Plus you'll need to learn to get the animal in range if you're used to farther shots. Your're only going to get one shot, and making that single shot count is the whole key to ML hunting. Now since I see you're in the Florida Panhandle, you probably have close shots at 100 yards or less, so in that case you're good to go.
So in short, loose powder, try several different projectiles to get the one that works well, and even then shoot at the range more than just sighting in the scope, since loading and handling the primer are a bit more involved than simply putting a round into the rifle and closing the breech. Get to know your rifle.
AND after all that, Good Luck Sir! We'd love to see photos of your hunt.
PS you might consider next year, perhaps getting a traditional caplock, and shoot patched round ball out to 100 yards. It's way cheaper, and much less impact on your shoulder, you can mount a scope on a traditional caplock if you wish, AND the deer are just as dead. If my flintlock can launch a .530 round ball through a deer at 110 yards, it wouldn't know the difference if I had launched a sabot round through it at the same distance.
LD