Robby, I agree with Taylor on the components. My pet peeve is trigger guards. The more commonly available commercial trigger guard doesn't have the correct scroll for either a J&S Hawken or an S Hawken rifle. Art Ressel used to and Don Stith currently produce a correct trigger guard for an S Hawken. Stith produces two different guards that are both correct for a J&S Hawken. TOTW did offer for a while one of Stith's J&S guards, but it is not listed in their current catalog or online. TOTW does still offer a correct (as far as the scroll is concerned) S Hawken guard (TG-Hawk-H-I). I don't know if this is a copy of Ressel's or Stith's.
On the issue of architecture and to build on Taylor's comments, common mistakes are too much wood left on the lock panels, slab-sided forearm, miss-shaped wrist, and wrong treatment or transition of comb into the wrist. These issues do not just apply to Hawken rifles. The same can be said of the different schools of longrifles, and especially to specific builders in respective schools.
There have been a number of good plans or blue prints for Hawken rifles published over the years and would be highly recommended if one planned on building a rifle from a blank stock. The issue of architecture arises when one attempts to build a Hawken rifle with a pre-carve stock. IMO, the common pre-carves from the biggest suppliers for both half stock and full stock rifles do not have high enough combs. Examples are shown below:
Compare the combs above to these.
Here are some other visuals in an attempt to illustrate the points I'm trying to make. Notice how wide the lock panel is on this rifle, the lack of roundness in the forearm, and the shape and transition of comb into the wrist.
Compare the above to this original S Hawken rifle. Check out the differences in the rear scroll on the trigger guards.
There are other "nuances that are important", depending on which period or specific original one is trying to replicate, but hopefully, you get the idea.
Taylor's work pictured above is an excellent example of what one can do with Don Stith's full stock parts set. For another interpretation, check out this link.
http://www.hawkenrifles.com/fullperc.html