Super hard question. I carry Skt #1, I.C., Skt #2(Lite Mod.), Mod, I.M., & Full. Plus I carry a note book and record each station's layout and my hits & misses. You might also want to track what ammo you are using. I would start with 1 1/8 oz. of #8, but I would have #7 1/2, #8 1/2, and #9,s in the bag.
(Just added) Oh, one more thing, if I was using a single barrel (like your pump) I would choke the barrel for the first shot, and hope for the best with the second shot, or in till my note book tells me different...
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