That, sir, is a very good question. I know of no single recommendable source devoted solely to archtectural comparisons and norms. Your sources are good for starters. Perhaps you could get the books that Dr. Whisker did on the particular schools, study them and draw your norms from them. He put out many books devoted to specific regions, and they fill a need. For Lehigh, see Ron Gabel, who did some monographs on that region that stand as a remarkable definition of the school. Also, consider the writing of Henry Bishop on Womelsdorf/Berks. This is all up-to-date material that you seek.
We who build have patterns, often 3/8" wood or so; we pull 'em out and cut away, and shape from there. Or, decide on a pattern and call one of the boys who rough cut stocks for a living...Miller, Rhode, Lepley...they are so fine tuned that you tell them the specific maker you want to replicate and they will give that exact stock back to you from a blank. Have the ramrod hole drilled, butt architecture set, and barrel inletted. You can also have buttplates roughed in and lock mortises cut, but, the more you have done, the more limited you are and the less experience you will have yourself. Just have these things thought out prior to ordering. Many professionals do this, at least the bbl. inlet and rod hole, which is a distinct pain.
Buy the best wood you can afford. Many people like curl the running the whole way out and I have found through experience that hard maple is easier to carve and work than wood from a softer tree. Learn to make your own small parts and inlays. Store bought ones rarely fit correctly and pre-fab inlays look just like what they are..machine made. That's what I've learned.
