Sorry, don't have Mr. Shumway's book.
Old Ford
Unless you have access to an original rifle(s) its simply not possible to build without proper reference books.
For you purposes Rifles of Colonial America vol 1 By George Shumway is needed. If the price is too high try obtaining one through your local library using inter-library loan. I have used this in the past. I think they let you keep them for 2 weeks or so.
There is a very fine early J. Dickert pictured in color in "Moravian Gun Making of the American Revolution" it is published by the Kentucky Rifle Association and ordering information is available on the KRA's web site. Being color the book is expensive for its volume of content. But the high quality color pictures of the rifles are priceless. The color photos are far more revealing than B&W.
Dan