No thoughts on the Charleville, but I've used two guns with Dixie's early Ketland lock: one for a short while, the other fairly extensively.
If I were wanting to use one today, on a gun that was going to see some use, I'd do some mods before beginning. Bush the tumbler hole with some of that oilless bronze bearing stuff Mr. Chambers sells in his Siler upgrade kits, and turn the tumbler shaft to match. Forge a new mainspring, and see how it works. Some of them seem to have really good-sparking frizzens, others will need to be half-soled. You may need a new frizzen spring too. As I recall, mine had an oversized hole for the topjaw screw, and kept coming loose--another thing to check, maybeso.
I used that lock for around 5,000 shots, and that is all I can recall repairing. It isn't a lock I'd go out of my way to get today, but if I had one, I wouldn't hesitate to use it on a gun that it worked with, design-wise.
I wouldn't mind getting ahold of one or two of the Lott locks, I always wanted to build a coach gun with one. Need any walnut?
Not sure I have any that is dry and large enough for a musket, but I could look . . . .