Let's see, you have a 20ga O/U, a 3-1/2" BPS for waterfowl (is that a 12 or a 10?),
Seems to me what you need is a 16ga SxS to fill your upland needs. For $900 you should be able to find a great little German 16 w/28" bbls (not many Germans around with 26" bbls). Probably won't be a straight grip though and it may have 2-1/2" chambers but ammo is readily available for it. Most people would call them "Guild Guns" with no makers name (at the Vintagers the German Gun Collectors held a symposium at which Herr Appel declared there was no such thing as a "Guild Guns") or they may have a retailers name like Kettner. It may have some wear but if it's in good working order it's a bargain and if you take care of it, it will take care of you.