Just as a follow up to this topic, I decided on the 275/65/20 Duratracs. Since I do not have mudflaps, I can report that there is absolutely no rubbing whatsoever at full lock in drive or reverse with a bone stock suspension setup.
I have not installed the drop shackles yet, but I am thinking about only dropping the rear one inch to leave some rake for when I do pull my travel trailer.
Thanks again for everyone's input!