Shrapnel has the right idea. I have an old LC Smith 12 ga that weighs 6.5 lbs, and I shoot one ounce loads in it. I would like it just as well if it were a 16 ga, but I don't think I would like it more.
Shotguns are about weight, balance, and fit, hopefully with a really good trigger or (preferably) two. Gauge is just something you need to know when you order cartridges.
