CD,
I don't think modifying the nipple to accept a 209 primer would work on the T/C Scout rifle. You would need to modify the reciever area to make clearance for the 209 primer holderand you would also have to modify the hammer. See pic's
I don't think it's worth carving up a Scout rifle to make this modification IMO.
I did experiment with musket cap nipples to get a hotter spark on the Scoutwith limited sucess.
In all the years shooting my Scout, I've never had a misfire. What scares me about the Scout is when I do a patch burn. I get better patch burn results out of my sidelocks than I do my Scout. This is why I tried using a musket cap nipple. Note: I did have to drill out the reciever to accept a musket cap nipple, but it's not noticeable.