So ``your" front clam is mounted to rotate on a shaft? As you say, that's probably better for everyday use (no need for disconnecting wires and hoses, little space needed in front of the car to open). The bobbin setup is quicker when you need to swap the entire nose in case of damage or to get full access to the front. I have the latter system and, while I've removed the front shell by myself, it's a much easier job for 2 people.
Regarding the ``cylinder" in the 2nd picture: you'll have to remove the filler unit anyway to check that the venting system is set up properly with a valve in case of a rollover. If your tanks are not connected (as in my case) there should be another venting system on the other side? I went through all this because I had a fuel leak in the filler system (leaving puddles at the gas station). Fortunately, my car came with fuel cells (air-craft style bladder system). So no need for action there.
Happy building!
