welcome to the Forum. good page to ask a que here so many shoot .38s.
my favorite is Red Dot for target loads. a flake powder usually burns cleaner and less flash than a grain powder my loads are around medium power. RDot is a peaky powder so watch overloads. can't recollect grain charge I use.
if you have any RDot to try get an Alliant data book or go online for info.