Rootsy,
You’re doing a fine job for your first gun!
For what you have now with your tang carving, you might look at George Schroyers work in that area for some inspiration.
One other thing, in my humble opinion, would be to slim down the cheek piece. From your pictures, it looks like it sticks out from the stock about 3/4", which is just too far. Also, the two big flats you have on the face of it would look okay on a Tennessee rifle, but that’s not what you’re building.
Generally speaking, the prominence of the cheek piece is just an illusion brought about by shaping, and not just shear bulk.
On most PA rifles, the cheek piece protrudes out from the stock only about 1/4" to about 3/8" at the most, as well as being tapered in thickness from the front to the rear. Thinner at the front, and a bit wider at the rear.
You mentioned that you have the RCA books. There’s a lot of pictures from the top of the stock, or from the bottom, so a look through these will give you a better idea of cheek piece shape and size.
Keep at it, and keep posting pictures as you go!
John