Don't forget Dave Keck's castings, although they are on the high end of the price scale, they are also on the high end of the quality scale. If you don't want to spend hours filing down a rough sand casting, then these high quality castings are for you, and they are correct. I use a lot of Reeves castings as well--It is good to have options.
It is too bad that so many times incorrect materials are supplied with kit guns. The term Verner is often used to describe any kit that is alleged to be a Bucks Co kit, and that attribution is based on the fact that the kit has a side opening oversized patchbox. There is considerable difference between a Verner rifle and a Shuler rifle, although at first glance they appear much the same. It takes time to study and learn the little nuances.
It is refreshing that Don is attempting to be as historically correct as he can on this build. Unfortunately, he may be far enough along on his build that correcting the butt plate may not be possible, but he already knows that he will not be caught in that trap again. First guns are always learning experiences, I wish resources such as this forum would have been available when I began...