Select one load and say with it.
Over time, your brain will immediately calculate the swing speed, lead, etc. that you need to break the target. If you shoot "heavy" or 3 dram loads you may get more tired at the end of a match than if you were shooting a "light" or 2 3/4 dram load.
Some shooters feel the "need for speed", especially from long handicap and on windy days, and shoot "heavy" or 1200 fps loads or "handicap" of 1235 fps loads. The faster the load, the more recoil it generates. The more a trap gun weighs, the more recoil energy it absorbs.
The great ATA Hall of Fame member, Ray Stafford, and many other top shooters have won many championships using the 2 3/4 dram load. As memory serves, the $100,000 event at last years Grand was won with a 2 3/4 Dram Federal Paper 8 load.
I like to shoot the 2 3/4 dram 7 1/2 load. My understanding is that at 27 yards behind the house, the larger 7 1/2 shot in the "light" load is moving at approximately the same speed as a "heavy" load of 8's.
If you feel the need to shoot 3 dram or faster shells, you may need to add a recoil moderating device or extra weight to your trap gun. Another strategy to reduce recoil is to shoot a Remington 1100 or other semi-auto.
My Remington 870 weighs 8 1/2 pounds with the addition of a Staub 6 oz. mercury recoil reducer in the butt. I shoot 2 3/4 dram "light" and 2 1/2 dram "extra lite" loads and can break targets from up to 35 yards (games - not ATA) behind the house.
If you reload, try dropping the velocity of your 1 1/8 oz. reloads to around 1100-1125 fps. This is the velocity of the factory "extra lite" loads. They smash targets and are very pleasant to shoot.
Just my $.02,
Ed Ward