TV tire size

Given the choice would you put a P275/55R20 tire or a P255/65R17 tire on a vehicle used for towing?

I've read here that many would prefer an LT (Light Truck) tire as their sidewalls are stiffer; so the additional trailer tongue weight and all your gear don't cause a lot of squirm when the truck is fully loaded. But they also give a harsher ride, especially when the truck is unloaded.

Will the narrow sidewalls of the R20 tire cause less squirm when towing? Apparently they will cause a harsher ride.