Since the hitch is designed to support its weight rating within all its adjustable settings, there is no question that this will work at the highest or lowest setting, assuming you use the correct torque to hold everything in place. Just like too loose is not good, neither is too tight with all the stress and strain a hitch goes through, you don't want anything coming loose or breaking under too much torque.
On edit: Here's a web site that might show your hitch. Clicking on the installation instructions should show you what torque to use:
http://www.reese-hitches.com/categor...eel_Hitches,87
(I think for the slider hardware it's 85 ft/lbs. for the non-slider it's 75 ft/lbs, but you probably want to confirm.)
Let us know what you find.