I have some detail shots, and I think a drawing, of the "plumbing" arrangement, But I'm having problems up-loading pics at the moment ( not just to the forum), when my PC "freezes" and I have to re-start to get anything to work.
EDIT:- Managed to load one pic, of a restored (static) P-51D at Duxford, just after completion, and before being moved to the American Museum for display.
This shows the 75 gal tank, with the rubber hoses and, at the tank-end of these, the glass "break away" tubes ( one of which appears to be copper here, probably "good enough" for a static, ceiling-hanging display, as it now is ).
The 108 gal steel, and "paper" tanks, had a similar arrangement, although one of the pipes ( from memory, the pressure line) ran towards the rear of the tank, on the portside on each tank, roughly just aft, and slightly outboard of the rear of the pylon.