Good stuff with the tanks, they should look good when finished and mounted.
I've been trying to find a clear shot of the 'plumbing', but so far this is the best I can come up with - I thought I had a close-up shot and a schematic drawing, but must be getting confused with the P-51 stuff I have on file.
PIC 1. Shows a Luftwaffe tank on a P-47 wing pylon. The plumbing arrangement on the 108 gallon tank was similar, but shorter, as the tank connections were further to the rear.
PIC 2. These are the connections on the top of the 108 gallon steel tank, and as can be seen, they were just aft of the rearmost retaining band.
PIC 3. Is an enlargement from a profile, showing the location of the pipes/hoses. The smaller diameter pipe and hose came out of the rear of the pylon, with larger, feed pipe out of the pylon near the top, where it angles up to the wing.
PIC 4. Shows the tank/pylon deflection bar in position, and retracted after the demonstration drop. Note, as this was a demonstration, there is no plumbing to the tank in the first pic. The landing gear compression rods can also be seen in these last two photos.
If you look closely at the pic Andy posted, it will also give you an idea of the location of the plumbing.
Hope this helps.