Having used many different types of hitches in trucks with 6.5' beds, I always advise to use a Sidewinder type kingpin box with a standard fifth wheel hitch. Hands down the best no-brainer option in my opinion. Solves all the problems easily.
Research all the options well and make an informed decision.
Scott and Liz - Southern NM
2012 Wildcat Sterling 32RL - w/level up (best option ever)
2007 Chevy 2500HD 4dr short bed Duramax w/allison
Reese Fifth Airborne air ride king pin coupler with Sidewinder