It will be a trade off. The ultralight is going to recoil very hard. However, you could target shoot with 7/8 or 24 gram loads. The loads cost a couple extra bucks and are harder to find but there are a few of them out there. Fiochi, b&p, and kent all make them. It will be great in the field but a little light for swinging at clays.
The canvasback has more mass for the swing and recoil. The trade off is lugging it around all day. You might consider a 20 ga canvasback. with some of the premium 3" loads a 20 can put the hurt on the pheasant. its weight is in between the two and will be a good compromise between swing, recoil, and carry. The 7/8 loads are standard so you won't have to go looking for low recoil loads.
Both guns come with hard rubber pad. First thing with both guns will be a recoil pad. If u do not want to increase the LOP that also means cutting the stock. Once you spend the extra cash on the recoil pad you are pushing real close to some guns that are a step up.
You are now in the price range of the new ruger red label, franchi, or maybe a used B gun.