Prepping to build (2) flintlocks, a 42" barreled Fusil De Chase and a matching French Tulle Pistol. The one big difference is I'm going smoothbores and using the same lock to make both. That way, I can carry one extra set of springs and parts and it will work on either arm if something goes awry. Plus both will use the same size flint and ball/shot combos. Only real difference in loads will be powder quantity.
I figure if I am big game hunting, I'll probably carry the rifle loaded with round ball and put shot in the pistol, for the occasional grouse etc, I might see. If birding/small game hunting, I'd probably keep a round ball in the pistol in case of bear etc. Seems like a fun route to head down and I've wanted to play with flint locks for some time.