If I were going to build, or buy, a trade gun that I was going to hunt with, I would get a chiefs grade, with 30" barrel, and an early Ketland lock. Most traditional standard grade trade guns, have a very straight stock, and very angular comb, that don't really make them a very comfortable hunting gun for most shooters. If you go ahead an make it a fowler, instead of a trade gun, you can add a few other comforts that will make your hunting more enjoyable, like a little more drop in the stock. I have owned two 20 gauge trade guns ( one chiefs grade in 30" barrel, and one standard grade with a 42" barrel), and have found them more than effective on everything but waterfowl. Hunting quail, and pheasant with a trade gun, is about as much fun as you can have with your cloths on.
Hungry Horse