Merry Christmas to you too Jaz!

I have quite a few such old texts, and I pull them up from time to time.
I seem to recall having a discussion with someone over the past few years (or more, might have been my late dad...) who'd owned or handled Ubique guns that had lancaster-esque 'invisible' rifling.
With a slow enough twist and the right kind of slight choke at the muzzle, I'm sure they could do well with shot and ball.
As Daryl has noted so many times in the past, a cylinder bore with properly-fitting ball can be very very accurate at reasonable distances.

I'll look forward to seeing how you do with these guns as they arrive to your bench.
Keep us tuned!

Cheers
Tinker