I purchased but haven't yet installed,a Draw-tite 18k Signature Series hitch for our 2008 F350 Super Duty LB twin-turbo diesel. We ordered a 2010 Big Horn 3385. There still building it. I'm not sure where on the bed it mounts, but if it is a little behind the wheel wells towards the cab, it looks like the top of the hitch will be at 51-52 inches. How can I get it to the 49-50 range without spending a fortune. Or will I need to send it back & get one that is only 12" high rather than 14"-18".