TC barrels are button rifled and have fairly shallow grooves, so they don't need really thick patching to fill the grooves. Also, the .490 ball recomendation is a starting point, not something carved in stone. You may well get better results with .495 balls and a thinner patch.
TC barrels usually come with a 1 turn in .48 inch "compromise" twist, a little faster than ideal for round balls but able to stabilize lighter bullets such as the TC MaxiBalls. That relatively fast twist means your best accuracy will happen with the lighter loads.
You can save a lot of money by going into a fabric store and just buying a yard of pillow ticking, just make sure it's 100% cotton, you don't want polyester in the patching material. Any tightly woven 100% cotton fabric will work, I have had good results with denim and a fabric that has some sort of flower pattern on it that Winns used to sell.
Just experiment, starting with a mild load and increasing it 5 or 10 grains at a time until you get accuracy. The rifle will tell you what it wants.
When evaluating accuracy, shoot at 50 or 25 yards, at 100 yards, crosswinds will drift your shot and you might blame it on your load. Also pay attention to the light conditions when shooting iron sights. Overcast conditions will have a different zero than direct sunlight so don't be too quick to blame a bad group on your barrel or load.