Lead will work on military muskets like your Bess. It will noticeably slow your lock time in all else. I personally was never able to secure my flints as tight as I want them using lead.
Correct
Lead was generally the choice for the robust military muskets. Leather is a better choice for the lighter fowling guns and rifles.
Note: I use leather to wrap the flints in my King's Musket. I don't see a significant advantage to a lead wrap.
Also correct
Although the "throw" the distance from the edge of the flint when the lock is cocked to the surface of the frizzen is huge in a musket, it is normally rather slow compared to a properly made rifle lock. That, coupled with the fact that the musket was to shoot and shoot with just a wipe of the underside of the flint and a wipe of the frizzen face and the pan, that inertia when the lock was severely fouled does make a difference. But that's for combat...
I think it was Chambers that would void lock warranty if lead was used!
Yes, and leather makes a very good choice for a rifle or smaller smoothbore, lock. There are some caveats. The back of the flint should rest bare against the jaw screw. Leather between the back of the flint and the jaw screw tends to absorb a lot of the impact, and thus as the edge of the flint changes from shot to shot, spark generation may be severely lowered with leather between the back of the flint and the jaw screw.
This shows the leather in relation to the flint
Here are two patterns of leathers. The top pattern when folded forms an opening and the leather and the flint then rest against the jaw screw. A circle is used but one can in the field simply fold a rectangle of leather and cut a V into the fold to allow the jaw screw to touch the back of the flint.
In the second pattern two holes are punched, and when this is used the jaw screw passes through the leather, keeping it in place, while tightening down the jaws onto the leather which then grips the flint. More elaborate, but IF you lose the flint, the leather stays in place, requiring you a moment or two to fish out a new flint and place it within the leather inside the jaws, and tighten the screw. The Top pattern are known to lose the leather AND the flint if the flint gets loose and drops out.
LD