I've mostly loaded shot for a 20ga fowler and a few times for a .58 smooth rifle.
I haven't loaded shot in years and checking my records - for both above guns it was 60 grains of Swiss 3F, under a .135" Circle Fly over powder gas seal wad, under a Circle Fly 1/2" cushion shot wad lubed with Gato Feo, 7/8oz of #7-1/2 lead shot, under a Circle Fly .070" over shot wad. Circle Fly wads are sized to the bore.
Always seems to take some testing to find what works best for any gun or bore size.