Woodstock,
Having seen your pictures, I really don't think that the nose piece you have will work. There is just not enough allowance for the wood under the barrel and your web is way too thick. I have had that problem since I inlet my own barrels and cut my own ramrod grooves; but I would send back a pre-carve that came to me that way. I cut my ramrod groove so that they are 5/32" at the muzzle and try to run them straight back. Usually they drift down a bit as you go toward the breech. I think the only fix you have at this point (and I have done this many times) is to deepen the ramrod groove at the muzzle tapering to the ramrod entry hole. I would use a plane for that, but a gouge and round rasp will do. It does need to be cut straight between the two points, and you will have to thin down and reshape your upper forearm. I would cut the web down to 5/32" at the muzzle and then make a one piece nose piece to fit. It should look something like Taylor's.
You are, of course, going to cut away the ramrod groove from the muzzle to just in front of the front ramrod pipe. I will try to get a couple of pictures for you of what it should look like.
Mark