Upland guns are special and there is no perfect gun except the next one or your buddy's gun that you covet.I'm a big fan of 16,20 and 28 and admit to owning more of them than I can shoot. My typical trip to the U.P. consists of 8-10 guns for the 5 weeks I'm there. This year will be different in that I'll be just taking long weekends but will alternate between guns and gauges so most get a turn.
My preferred barrel length is 26 and choked IC/M or SKT/SKT. I recently adopted a VHE 20 skeet with a factory vent rib which will get a work out.
I'll hunt a couple of times with a 12
but in my defense it's a British light game gun and I use RST 2 inch shells with 3/4 oz of 8's. Just like a 28.