Rick sent me a swivel base he bought from Sportsmobile for a 1999 Chevy that he used to own:
The bolt pattern is the same on my 2005 Chevy. I'm happy with the result. This gives us a comfortable seat for reading etc. My TV can even swing around to face the seat.
I put seat covers on my seats. They give me a little bit of storage and protect the seats.
I removed the plastic door threshold (not sure if that is it's name), installed the seat and base, then I put the threshold back in place.
I can swivel the seat without opening the door. I think the most comfortable position for reading will be with the seat slightly reclined and facing the drivers seat; then I can put my feet up on the drivers seat