Like you, Don, I go for 1200fps loads. For 16 yard Trap Singles, I use 7/8 oz #8 loads. It doesn't really take bone crusher loads to break clay birds, so I use light loads to conserve my components and my shoulder. Yes, shotshell powders and handgun powder are one and the same. Convenient, huh? I use Red Dot and 700X, both of which are excellent handgun powders.
Don
I'm a cast bullet shooter!
You can even get away using Bullseye for light 1oz loads.
You need to be careful though.
They tend to gwow like wabbits.