I'm surprised no one mentioned HS-6; even though it's too slow for the application. HS-6 likes heavy bullets; at least in order for it to to run clean with a consistent burn. It'll work fine with 124's - if you pump them up to defense level. But it behaves best under 147's . . medium to strong loads.
For your application, between W231 and HS-6 - it's a no-brainer. My range shooter 115 using W231 is 4.6 grains. Yields 1068 f/s thorugh a 3.7" bbl Kahr CW9; and 1124 f/s through a 5" Beretta 92fs. Your mileage may vary; always do your own workups. For me, this loading shoots and cycles nice. Make for a good day at the range.