Thanks, Stu, Phil and Mopar Man. I'll be towing with a Ford F150 w/ Ecoboost engine, 143" wb and 3.55 rear axle. The maximum tow capacity is rated at 9,800 pounds with a WD hitch. Conservative by nature, I would like to keep GVWR to 80% or about 7,800, so I'm looking at units with dry weight...