Dave,
Off the top of my head, I can't think of any with a concave swoop after the 1780's, until we get into the maybe 1860's and 70's. in other words early breechloaders. I will see what I can find though.
The other style you mention, (Comb merging into a very short wrist) while very distinctive, might be a shade early for your build, but maybe Not!.
I am afraid I loaned both my Manton books to someone a few years ago, and they have yet to be returned!
I know Twigg is a bit early Dave, but here is a relic with the sort of nose to the comb I think you are looking for. Is this correct?
An old Weston I have has the abrupt style. It is likely 1820's or thereabouts.
The one below is maybe a decent example of halfway between the other two, but it is a bit early, maybe 1815.