Our first 5er had a 17 percent pin weight. It pulled beautifully by itself or with a 3400 lb boat behind it.
2nd 5th wheel trailer had a 20-22 percent pin weight and it towed like a sick hog on ice.
Current 5er has a 19-20 percent pin weight. Zero towing issues with it.
The industry tells us a 15-25 percent is recommended.
I pull GN equipment and a 36' tri axle stock trailer which can be loaded at any percent hitch weight. I pulled 18k GN trailers with around 12-13 percent on the ball and no issues.
Half ton towable ?? Our 1/2 ton trucks run from a 6xxx GVWR with small 3500 rawr/P tires and 1500 lb payload up to 8600 GVWR and 6000 rawr/E tires and wheels with over 3000 lb payload.