[roadcat]

Has to be quite a trick to get the fuel flow re-established in the "belly flop" position.

I don't think it matters what position the ship is in. The fuel flow and mixing is done with high-pressure pumps. I read somewhere about SpaceX using a rocket engine that drives the pump mixing the fuel. Old tech but refined by SpaceX.

[ProtectOurFreedom]

But the pump has an inlet pipe which has to be at the bottom of the liquid...which is different vertical vs horizontal.