Re. Smashed flints:
Just about any lock will work (sort of ;-) for percussion.
Imco(in my curmudgeonly opinion;-), the very best flintlock you can buy is barely adequate".
There are a few happy exceptions, like my Charleville, and a Miquelet replica, but you'll save time & aggravation if you spend the $s for a top-quality lock in the 1st place, and use good English flints in it.
Long ago I ran sawn flints from Gunther Stifter in my Bob Rller locked flingers, but the precisely sawn agate(?) struck frizzened in the same place each time and made frizzened surface look like a washboard as the 1st cut bounced the frizzened back and then as the frizzened spring shoved it back against the descending sawn flint, a 2nd divot got sliced out of the frizzened.
My frizzened had been hardened deeply enough that they still sparked well after I ground them even/removed the divots.
Using real flaked gun flints that don't strike in exactly the same place will increase frizzened life a great am mount before you need to replace or half-sole your worn frizzened.
Spend your $ on plain stock wood, go smoothbore instead of rifled, skip the facy gingerbread carving and inlays, but DO not "save" on your gunlock!
If you don't get the best flintlock available, you are storing up grief & aggravation.
Alternately, you need to learn to be your own "lock Doctor".
After reading all you can, spending $ for tools, locks, parts and several years you may (no guarantee)-: attain heights of "barely adequate"....
(Just get the best lock you can in the 1st-place!
Dave PS spell-check continues to make a fool out of me....you can imagine how great a flintlock mechanic I am ;-)