Hey Tassos.

The carbon look-a-like plate is actually a plastic plate with a carbon print on it.
Sandor of Digitech sells this stuff.
The "fueling" line to the UAT is 4mm, from there the fuel line to the main tanks is 6mm.
Together with a low voltage operating "fueling" pump the "fueling" pressure will be almost zero.
Even if the fuel valves of the Jetcat leaks, I can't image the fuel go's through the not operating pump.
Ofcourse it never hurts to install a ball valve after the pump.
Will let you know about the maiden! [8D]