I use a Reese Signature 16K, with a 10" nylon plate and no grease. The only problem I've ever had was when pulling in, then landing gear down, and handle won't release because of the king pin pressure against the jaws. In that situation, I just back the truck slightly to release the pressure, then the handle comes free immediately. The Reese has enough swivel side to side that leveling is not a problem.
2003 Ford F-350 V-10 Crew Cab 4WD Long Bed
2004 Jayco Designer Medallion 29 RLTS 5th wheel
Bill, Gayle, and Mindi (dachshund)
Retired at last !
Nothing is foolproof to a sufficiently talented fool.