If you are considering/already have a weight distribution hitch system, my setup might be relevant. I have a newer (‘20) 2500 and use an “Equalizer” hitch system pulling a 24’ enclosed. That required me to get a 9” drop shank so that my trailer would be within 1” level ft to back. It also redistributes weight from the back of the truck to the front tires depending on the adjustment dialed into it, as well as reducing sway. I believe the standard drop shank with the kit was a 6”, so i had to get another one at 9” drop for my trailer design. Not sure if that helps you any.