Speed is not as important as pattern density. You don't want a load that blows holes in your string. Have you patterned your loads to be sure this is not happening? I used to shoot a LOT of trap, and the load that worked best for me, even with "yardage" as well as 16 yds. was 17.5 gr. of 700X, Rem. RXP wads, #209 Win. primers, and 7 1/2 shot, 1 1/8 oz. All stuffed into AA hulls through my MEC 650.
I haven't loaded this for many years, as my interest took different turns. I don't know if RXP wads are still available. If not, AA wads should work also. Just check your shot column height.
Keep poppin' at them------it's a great shooting sport!!!!!!