NO "EXpert" however all I have ever shot is Pyrodex,, from GA to Maine,it works for me in my capper. Read where it takes a hotter ignition source to go off. Used it in my Underhammer,Lyman GPR and capper pistol worked just fine.. Clean up is the same ,clean and clean again,,just like any BP firearm,,,, Then you have the die hard that would rather be eaten by a bear than shoot it with Pyrodex,,to each his own'
Read lots of posting where it isn't as reliable in Flinters due to the ignition requiring a hotter heat source to set it off,,can't say as I have never shot Real Black Powder nor shot a flinter.
I would use what I could get before I would stop shooting..
Do what works for you,try both and then decide!!!!