If you have only one car seat, where is it?

We have his bucket seat in the middle, but he just hit 29" so we are about to switch to a RF convertible. The infant bucket is really easy to get out from the middle, but I wonder if it will be easier to take him in/out if I put the rear-facing convertible on the side...

If it matters, I drive an Acura RDX (crossover/small suv) and DH drives a Mazda 6 (sedan)