Another powder to look at for the trap load is Hodgdon International Clays. I've been using that powder for any low weight shot shell for 20 years. It is an incredibly clean burning powder, and gets things moving. I can't recall the weights, but the bushings are below. Makes a nice zippy shell that I compare to the STS or AA higher end shells... Just no where near as dirty.
31 MEC bushing
Claybuster WAA12SL clone
33 MEC bushing
Claybuster WAA12 clone
Remember, shoot straight and shoot often.
Good... Bad... I'm the guy with the gun.