I think the Pease rifle has the Lyman lollipop back far enough to avoid the bolt. I imagine the right thumb has to be in front of it, however. While that seems awkward to me, I suppose it will work. I wonder if Pease put that on the rifle or if a subsequent owner did it?
LRF, I just skimmed your thread on your recreation and you mentioned making a tang sight, but I do not see it in the final pictures, unless I missed a few. Did you make one from scratch? The Lymans I have, are not my favorite. I prefer the Marbles, if it is to be a lolli style.
Parabola, is your rear aperture sight riding on the bolt? It is a bit dark to see what is going on in that picture but I cannot imagine it doing otherwise given the position. How does it work?