IMO, it depends on what type of boat you fish from, smaller Private boat vs a bigger, head boat (and more people, less moveability).
The 6' can help you keep the fish from rubbing the line on the hull of the boat.
But I don't know if 6" can make that big of difference since you're 6'3"!
Either one will work for you, but the 5'6" is a stronger rod vs the 6'.
If you want to pull on one before you buy, come to the next BassProShop get together and I'll bring all 3 rods!