The three way valve from the autocockers won't work. You forgot that they also have an exhaust vent hole in them. However if it wasn't for that then yes it could potentially work out. But you'd need room for both tanks in the nose and in close as possible proximity to the engine.

The other deal I mentioned isn't a drip tank. I was talking about a full on supply on demand float controlled shut off valve so that regardless of how fast or slow the engine demands fuel the level in the float bowl would remain constant until the supply tank over by the wing was drained dry.


But this brings up the next question. Why do you want to fly for SO long? For most of us up to around 10 to 15 minutes is plenty. With that much flying time there's lots of time to reach altitude and take pictures to your heart's content without resorting to extreme solutions.