Pyrodex pellets for revolvers, as far as I know are only available in .44 cal in 30 grain size. I use them all the time in my Pietta 1860 Army. They work great. I wish they did make them in .36 cal 25 grain.
Don't use much pyrodex here. The way I see it. If wanting convenience. Those pre-measured drop in pellets are the way to go. If wanting a specific powder charge tailored for your rifles utmost ability. Granular Pyrodex than.
Always pay attention to your weapons manufactures guidelines concerning suggested loadings and the proper propellent/s to use in their products.