I would get high rated tires and skip the 19.5’s if I did it again and was under 8k on the rear axle. When I got 19.5’s for my F250, they rode like hell, had traction issues and tracked lane to lane on the freeway, especially the first 2k.
This was my experience in my truck. Super duty’s are beefy trucks, tires are the weakest point, imo. Between work and home, I have/had 5 in the last 10 years, great rigs. Most of the guys on this thread have great advice and tons of experience. Every situation is different, everyone’s comfort level is different. Make your own calculated decision. . Good luck.