Your rifle has a 15/16" across the flats barrel.
Is your gun a flinter? There are some drop in barrels available. The ones I use are from Green Mountain barrels. This is my 45 cal deer and antelope gun.
I have both inlines and side locks. These old guns are easier to clean. The inlines are a pain in the butt to clean. As far as accuracy goes I will put my side locks up against any inlines. The barrels come off and are just simple.
The con is these guns are heavier.
But the heft is actually a benefit when it comes to being accurate.
These TC's can be fitted with better sights. Mine all have Lyman 57 SML peep sights. They also have Lyman 17AML globe sights with lee shavers inserts.
The globe front sight has a removable insert. I use Lee Shavers inserts. These are BPCR inserts and are used out to 1000 yards. My son like a crosshair, I like a single post and bead. This is one of my 50's
Many guys buy a inline then struggle to figure out if it is legal in their state or other states.
Mine is legal in every western state I would ever hunt in. Mine can accurately shoot out to 300 yards.
This video might be of some help to you.
https://youtu.be/ibU-5uCuy_I
In this video I tested my guns at high elevation to make sure that they shoot where they should.
https://youtu.be/JmXOFFWCK_0
In my opinion you own the perfect muzzleloader. You just need to turn it into a Hot Rod.