Not sure if you have enough wood material to change at this stage.
However, yhou could just get rid of that metal ramrod channel spacer and go a bit deeper down on the inlet.
I am new to stock building myself, but it seems you might have just enough material to make a ramrod channel left on the gun.
The picture do not show how much work was done on the wrist and butt section.
Also, if it was me and I was spending this much time on the gun, buy a good lock if the gun is flint. If the trigger is nice and reliable in a percussion, then stick with it.
If your going through all this work, might as well have a really good lock for it.
You did not specify the barrel or caliber.
However, from what little I have seen of traditional guns; a typical modern made muzzleloader has a relatively short and big octagonal sized barrel.
A marshall or jaeger inspired build would fit that barrel a bit nicer. Although most of them were swamped.
Also, get a traditional sight on the gun. The adjustable one usually looks out of place. On top of that, they can drift easily. My lyman GPR did.
Most CVA, Lymans, and T/C are usually hawkens inspired pieces. A wooden fullstock hawken is a really nice gun.