I've used both Pyrodex and Goex in a number of TC Hawken percussions and now flintlocks...using real BP with it's lower igniton temperature, there's NEVER a question about it going off instantaneously.
And although Pyrodex RS served me well for several years until I learned about Goex, I did have a few instances where I got hang fires, and one of those times I was looking down the barrel at a 6 pointer.
They both require exactly the same type of thorough cleaning and both respond perfectly to lubes like bore butter for shooting without having to wipe between shots...so my suggestion would be to use Goex FFFg.
Note: Goex is only $9.90/Lb delivered to your door if you order it by the case from JJPyrotechnics in Moscow, PA...it's outstanding stuff...fast, clean, and accurate.