Manufacture modified outer fuel filler flanges

Previously I considered the following tweak to the fuel cap flange design: a) Remanufacture the outside fuel cap flange WG-FLG-004-X-A- from 2.4mm 6061-T6 rather than the original 3.1mm (0.7mm less - almost the same thickness as the fuel tank skin); 2) Chamfer the inside fuel cap flange WG-FLG-005-X-A- sufficiently to make the fuel cap frame rim lie flat on the flange surface, rather than sit above it slightly as indicated in the plans (attached, detail B).  The thinner remade WG-FLG-004 means the fuel cap will lie flush with the fuel tank skin surface more precisely and reliably without risk of it setting at a slight angle. 

Since the total thickness including skin is about 3.1 + 2.4 + 0.63 = 6.13mm I have on order 73 TA 5-4 (4 x 11.5mm) Sealed Dome Aluminium Steel Blind Rivet Grip Range 5.5 - 6.5mm

I did a trial setup - nice result with the fuel filler cap level with the skin. I am assuming it will be possible to squeeze the flameseal to a thin layer. If not the filler cap will be very slightly proud of the skin, a not displeasing result. Better this than it being inset relative to the skin, which does not look so good.