My advice is to select one load, a “Light Trap” load, and to shoot it from the 16 yard line to the 27 yard line.
A "Light Trap” load is 2 3/4 Dram Equivalent and 1 1/8 oz of shot which yields 1145 fps. With either 7 1/2 or 8 shot, this is all you need back to the 27 yard line.
A "Heavy" trap load is 3 Dram Equivalent and 1 1/8 oz of shot which yields 1200 fps.
"Lite" and "Extra Lite" loads with 1 1/8 oz. of shot range from 1100 to 1120 fps depending on the manufacturer. They are sometimes marked 2 ½ Dram Equivalent. These loads will effectively break targets back to the 27 yard line.
The lighter 1 oz., 7/8 oz. and 24 gram loads are all over the place in velocity from 1100 fps to over 1300 fps.
As you gain experience with light loads, you may become amazed at their effectiveness and lack of recoil.
Many beginners shoot 3 dram 1 1/8 oz. loads and quickly get turned off by the recoil.
Watch the shooters who are shooting the heavy loads. In most cases they will be using an automatic or a heavy gun with a recoil reduction system.