I don't know about lifting the spine, David. Remember, he says:
"The first thing to be attended to is to keep the razor perfectly flat on the strap during the whole time of strapping. The reason for this direction is . . . that, if the back is raised, the extremity of the edge will be too much affected by the leather and the composition, and, together with it's roughness, will be deprived of it's keenness."
You're right that his main piece advice seems to be keeping the strop as flat as possible, and I think Kingsbury would much prefer a paddle strop to a hanging strop. I don't think the latter was used much at all during his time, because when he talks about the perils of elasticity, he focuses on strops sold with bases of flexible wood.
The method of stropping that he advocates is not too dissimilar to what most do here, but he recommends moving the razor "obliquely across the strap from the point to the shoulder." If I'm interpreting that correctly, it means keeping the razor's edge somewhat parallel to the bottom of the strap, and, starting with the point on the strop, moving diagonally upward to the left (if you're right handed). Upon reaching the top of the strop, with the point now hanging over the edge, reset its position while turning the spine so that the point is resting on the right side, then pull diagonally downward to the left, "point to the shoulder," resetting again at the bottom and repeating.
To further recap, always moving "point to shoulder" on the strop, according to Kingsbury, will eventually shape the "teeth" so that, they point very slightly towards the heel (such as with a saw), allowing the edge to cut much more efficiently when drawn obliquely away from the ear while shaving.
Anyway, I'll definitely be trying this out with the next razor I hone. If anyone got something different out of it, please correct or add to what I've said.
We are on the same page on this but yeah, I think I skipped the part where when you do your flip, you keep the spine on the strop and slide it over before the next pass to ensure the point to shoulder thing (would be a bugger with a finished spine lol).
I'll try it that way, but it'll be work to change up what I am so used to doing. I have to read the honing section, but does he advocate that one hones in a manor that keeps the teeth angled from point to shoulder as well?