I first started out with washers increasing a bit at a time till it felt right. The added height was very close to one inch so cut some one inch square tubing covering the original contact area - drilled some holes and done. Was just as solid as original setup.
Suzie & Chuck USNR USAF USCGA
Challenger Owners Club
2015 37KT Challenger, Demco Commander tow bar, Ready Brake, Sewer Solutions, Safe-T-Plus 41-230, 5-Star tune with 2014 Ford Fiesta behind us & 385 FastTrack kayak inside.