Well I've settled on fuel gauges, they're are a little heavier than I would have liked being all stainless construction, but for pure simplicity they are tops!! I'm intending to install them at the root of my outer wings and they'll be flush with the surface, the idea is that I'll be able to see them from the pilots seat, though I'll have to lean a bit to see the starboard one. If you look at my yahoo pics you can see the Aluminium mounting ring I machined up this morning, It'll be floxed in place so the gauge is flush with the upper surface of the wing.
Gav http://au.pg.photos.yahoo.com/ph/glasseyegav/album?.dir=a154&.src=ph&pok=phi2Hacbo9aw67de