Since the right tank is tested I could move the manometer to the left tank for the leak test.
Improved setup in the living room:
I mounted the fuel sender plate, gasket with some Fuel Lube and torqued the M4 bolts to 20 inch/lbs.
The first test failed very fast, with some soapy water I could identify the cause:
I removed the sender plate, replaced the gasket and mounted it again.
There is no immediate drop, so that’s good, now fingers crossed for the upcoming days…
See Fuel tank leak test for more info.