"The owner has been talking to an engineer who has helped set this system up."
There seems to be your first problem, tell the owner, you need a sealed and signed set of prints from the talking engineer, talk is cheap, the owner has to pay for the design, i would not touch that job without a sealed print.
I flew into both first class airports, and grass strips, that you could not find on a map, some have the best fuel equipment and services, and some have nothing but a drum and hand pump, when your dealing with fuel, safety is first.
"engineer who has helped set this system up."
Helped or is his seal on the job? , does your insurance have E&O coverages for design work?
[This message has been edited by LK (edited 08-19-2006).]