Actually, Geoff asks a very reasonable question. If I were installing those tanks, and space allowed, I would install them as in the RIGHT photo. Reason: at low fuel states in terms of volume, the fuel surface will stay higher in the narrow "lower" part of the tank thus reducing the risk of uncovering the clunks in a nose down attitude. The fuel pickup holes in the BVM F4 tanks are at the the top of the tank as in the right hand photo so that is not a problem. Or have I missed something (apart from slightly changing the vertical C of G) ?

Regards, David Gladwin.