I have a cheap bulb siphon with tubing as an emergency backup so I can stick one end in the Aux and the other down the main and squeeze like hell. Would be a total pain in the arse but possibly a life saver in the event of a pump failure.
I really like the long ranger set up, you know how much is in each tank, you can fill them separately, they are isolated from each other you can top up on go.

