pointer, if you are talking about regulation skeet, heavy shells are not required. They will beat you up needlessly. By that, in my opinion dont use anymore than you need. On average the range isnt but 20-25 yards in skeet. I would reccomend a light target load ...say a 3 dram 1oz or 1 1/8 oz of #9's. Using heavy field loads will only cause more flinching and fatigue to you. It's a fun and relaxing thing to do, you might shoot 100 rounds before ya know it, but your sore shoulder will remind you. In skeet you are shooting at crossing targets, once you get the timing down there aint nothing to it.
The 11-87 should be able to digest light target loads, if it dont there's something wrong with it.

doubleA