Don. NO, I have found no problem using a lead wrap around my flint in more than 25 years of use. My wrap is much thinner than 1/16" however, and the weight of my wrap on my rifle is about 17 grains, and the one on my new fowler, about 32 grains. At 437.5 grains to the ounce, these weights are insignificant.
The weight does help the flint drive into the frizzen and scrape steel off a properly hardened frizzen face. The lead has the same effect as a lead weighted hammer, in that it prevents the hammer from bouncing on impact. ( Lead(shot) loaded hammers were once referred to has Dead Hammers).
The lead weight also helps to accelerate the fall of the hammer when it passes the top of the arc, and that extra speed helps to cut steel when the edge hits the frizzen face. Because the cock only goes back to about 10:30 o'clock when at full cock, the acceleration on the down side of the fall compensates for the very slight slowing that occurs when extra weight is is back at the full cock notch, and has to " climb " the arc to reach the 12 o'clock position.
All this is helped because the mainspring, on guns with " V-springs ", is compressed the most at full cock, and the release of energy pushes against the weight of the cock, flint, and wrap, the strongest in that position. When the cock comes past 12 o'clock, gravity begins to assist that mainspring, and speed up the fall of the flint.
Locks with coil mainsprings are not going to behave the same as a "V-spring". They do benefit from the added weight abd gravity assisting the fall of the flint to the frizzen, but the coil spring does not usually " stack " its energy at the full cock notch.
I once weighed the leather wrap used by a friend of mine. I believe it weighed about 5 grains less than my old rifle wrap, that has been squeezed, and trimmed over more than 25 years of use, on countless numbers of flints. I have not measured the thickness of my lead wrap, but if you, or anyone else is interested, send me a PM and I will get out the micrometer, and measure if for you.
I don't see the point. My friend's leather wrap was made from thick tanned leather, and it was not trimmed close to the jaws. If he had used raw hide, ( parflette) or at least trimmed down the part sticking past the sides of the jaws, it would have weighed a bit less. My wraps tend to come from balls pulled from the barrel after dry-balling, and I just hammer them on my bench vise anvil until they are flat and thin enough for me to easily bend around my flint. Then I trim the excess lead off with snips or a knife, or both.
I do use a dull knife that is heading to my honing stone to be resharpened, as lead doesn't do the edge any good. No point in ruining a good sharp edge! I do keep an extra flattened piece of lead in my flint wallet that goes in my field bag, just in case. Its not as thin as it should be, but it can be flattened some more when needed.
I have lost a flint out of the cock on one occasion, due to not having checked the cock screw before I fired the gun, after a long period of storage. That, as they say, was operator error! I have seen other shooters hammer the edges of the lead wrap over the sides of the lower jaw, just to keep the wrap from moving sideways, and the flint with it. I will have to do that with my next flint wrap- if I remember to do it.