The best charcoal star I’ve used is Bill Ofca’s. It’s: KNO3 15 charcoal 9 S flour 2 dextrine 1 ball milled. He would do it as for lift powder, 10-20 hours, but probably using his bocce balls! I find 2.5 hrs. with brass balls in a rock tumbler is good enough. The fineness of the charcoal you use probably doesn’t matter in this recipe, as it’ll all wind up comminuting whether you start with air float or anything else. I’ve only used KSI/Skylighter air float. As opposed to most charcoal stars, which depend on coarse coal for tailing, this one is designed to be broken hard and burn very vigorously to scatter sparks. Designed for cut stars and a flash break, it’s also good pumped as a comet or candle star. No priming is necessary. Don’t try to dry big ones too fast, because crusting may occur. You can also roll it as a layer in a color-changing star, but it’s a little easier if you mill a mixture without dextrine and then bind with dextrine sol’n during rolling.