I used .5 in nyla flow from Spruce, from all three tanks to a 4 position selector valve. It is sleeved with polyethylene tubing where it goes through bulkheads and bonded to any surface it touches with silicone.

I originally used the plastic compression fittings from spruce but found they were too hard and subject to brittle failure. I could not find aluminum fittings and went with brass fittings from Mc Master Carr.

I mounted the fuel pumps provided with the kit on the outboard rib of the gear well to serve as boost pumps, just inches from the finger strainer, they make vapor lock a non problem, even with mo gas. I always keep av gas in the header tank and use that for takeoff.

Advantages are, each run is a single continuous piece of tubing, abrasion and fatigue resistance, light weight, fairly easy installation.

Obviously this is all behind the firewall. So far no signs of fatigue cracking, abrasion or enbrittlement. The material is as flexible as it was new after 15 years, 2100 hrs.

Come to think of it, it was not very flexible when new. To make small radius bends I had to heat the material with a heat gun almost to the melting temperature, then bend it to a slight over bend, and let it slowly air cool in that position. Once cool it is permantly bent to the desired shape.

I won’t pretend this is simple, experiment with some scrap. The thermal  conductivity is low so you have to heat it slowly and evenly, keep the heat moving. It becomes transparent just before it melts. The right temperature is in the transition to transparency. Heat only the section you want to bend, not the ends that will go into the fitting.