My favorite 20 is a Beretta Onyx with 28" barrels, 3" chambers, and Mobil Chokes. It's light, reliable, pretty , and will do anything a 20 ever needs to do. The old Onyx with 28" barrels can be hard to find, but worth looking for. And Cole can fit double triggers and fancy wood if that is your preference.

If you are seriously thinking abut another 16, consider a Parker VH on the zero frame. Carries and handles like a 20, but if you have to go to non-tox, the 16/0 may not be a good choice because they often have light barrels.