I like # 8 shot back to the 23 yard line. Use #7 1/2 shot from the 23 to the 27. Personal preference, the are those that break them consistently with 1 ounce of # 8's from the 27.
I use 1 ounce of #8 from 16-27. I change chokes as I move back from the 21. LM from 16-20, M from 21-24, f from 26 to the back line. This is also a personal preference. Try diffeerant loads, shot and chokes to see how they effect your shooting.