This is the bottom of the first stage tank:
Do you have some more information on that? esp the report that contains that drawing of the propellant feed system.
I would have bet almost anything that the fill/drain would have it's own direct connection to the main tank to avoid having a split in the feed from the tank to the center engine. Wouldn't this split juncture cause unwanted turbulence and possibly cavitation?
What could be the diameter of these openings....because these openings seem small for the flow rate of the propellant...or the feedlines dia increases afterwards??