Sanjay----- On my airplanes I use automotive rubber fuel lines. They don't
harden and last forever.
On another note regarding header tanks. On the Dragonfly we leave the fuel
pump on all the time and then the header overflows and feeds back to the
main. When I turn on my master, my pump is also on. No separate switch to
forget. You may have to put a small restrictor in the line if the pump is
pumping faster than the gravity return, but this system has worked great for
me for twenty years.