I wanted a lot neater and reliable fuel system than rubber pipes, which have to be replaced after 5 years. The Andair Gascolators are a good product, which have water drains and a PTFE filter to help prevent any water passing through to the engine.
My Gascolators are attaching directly to the Andair fuel selector, one for each tank. As the Gascolators are at the lowest point of the aircraft, and on the suction side of the fuel system, any water will naturally settle in the bottom which can be checked. The only disadvantage with this is that I will have to have a slightly lowered access hatch under the aircraft for cleaning and maintenance.
There is a shut off valve added in-between the tank and the Gascolators so to shut off the fuel for filter cleaning and maintenance. I have used aluminium pipe on one side and Teflon tubing on the tank side because of possible movement and expansion of the tank.
The seat pans will be designed as to not allow the shut off valve to be closed while they are in place, as this could make me have a bad day