Look into Arkansas Black, I think it might be a good higher producing bitter than Kingston. Also you can never go wrong with Honeycrisp, it produces a huge amount of flavorful juice for the footprint... and of course they ain't bad eating either! The old English cider varieties really aren't very productive overall. Cox's Orange Pippin is one I would avoid. You could get Kidd's Orange Red as a better alternative, although they go soft fast and are thus more difficult to press.
Sorry to hear that Tony at Maple Valley is not doing so well... he is super knowledgeable, I met him several times and he is quite a character. I called him last fall to see if his store would be open and he said he's pretty much called it quits, not selling any fruit anyway but I don't know about scionwood. In any case I hope he gets well soon.