Rob, I dont think you will find a substantial difference in taste between prime and choice, although, I could be wrong. I don't remember anyone ever saying they have cooked a prime cut on this site. My butcher told me there is quite a price difference between the two. It would be a shame to pay more and not be able to tell a distinct difference between them, don't you think?
Since it is going to be a late November cook, you might want to start w/ more lit coals than normal if it is cold out. Other than that, you'll be fine!!