I'm looking at getting the hi lo plug in posts for the boat. Has anyone used them for theirs? They say they are only B class. I know I've seen them used as a class A seat, meaning it is used for driving over 5 mph. Also, I believe I need the 12 in post but I can't figure out how tall it is after you plug it in. Does anyone have one of these that could measure that for me? I'd greatly appreciate any input. I'd like all the seats of the boat to be removable if possible. These seem to be the best option.