Unfortunately, I had the same problem. I think you will have to take the car to a store and ask them to trial fit a few. Whichever one you choose, the passenger will be as far forward as they can be just to get it to fit. Then you have the problem of getting the seat rails to lock, as you have to move the seat partially back for that to happen. Difficult when the baby seat is hard up against the passenger seat.
Now that they are both forward facing, I don't have that problem

Except now I get in trouble when they ask their mother why her car is so slow.
