Michael,
You made a good choice. Jim has done a great job recreating the SMR that is super close to the original. I would recommend you research the original rifle and look at the photo's for info concerning the patch box design and nose cap configuration. Jerry Nobel's book "Notes on Southern Long Rifles Vol. 1" has photo's of the J. Whitson rifle on page 124 and 125 that will give you an idea of the patch box and nose cap as well as the rest of the rifle.
This rifle has been a favorite of mine for many years.
Roger Sells