Thanks for the input. I originally considered a 12ga, but decided against it as they're too heavy.
I'm looking at the Remington 870 SPS 20ga which has a 3" chamber instead of 2 3/4", and weighs only 6lbs, and 39 1/2" overall (18 1/2" barrel). The 12ga is 1 1/4 pound heavier and a couple inches longer. And that's with the pump action. The semi-auto's are 2 pounds heavier!

Figure the 20ga would be better as I also plan on using for stalking game as well as hunting the blackies over bait.