pin height adjustment

How many inches adjustment is there in the pin box for elevation change? My TV is a '08 F350, CC 4x4 long bed with the 20" wheel option. My hitch (Reese 16K dual swivel) sits at 52" at its lowest setting. I understand that the pin sits at 46" off the ground on the 3400RL but I don't know if that would be the highest it could be adjusted to. I can also gain 2" by having the blocks changed on the truck from 4" to 2" but that still leaves me about 4" off if the pin can't be adjusted up. Any info would be appreciated as I anticipate delivery June 2 at Pricebusters in Richmond. Thanks for your help.

Here are a couple of pictures where you can see the adjustment holes. I think you get 2" of adjustment when you move up or down one hole. You have to be careful how far you raise the pin so you still have bed rail clearance. If you hitch is too low in the truck you may have turning radius clearance with the back of the pin box against the bed rails. One picture shows my trail air. I had to trim some material off the back of the pin box for added clearance. The stock pin shows what the pin box looked like before trimming.

Not looking at the same unit. We took delivery of our new 3400RL Saturday and was concerned about height adjustment also. As you will note in my sig we have similar vehicles. When all was said and done we ended up with 8" between the 5Th and our bed rails. Were towing with a Pullrite Superglide and the Trailair option.