TOPIC:

Just check the distance - so it is 7.5 measured between 2 - 4. (measured form the 1 I get 7.5 just at the edge of the flange).
And all measured without the gasket.

For true adjustment of course you have a gasket there.

This is 7.5 mm from that outside edge, without gasket. With gasket about 1 mm less to the lower flange edge (3 in my previous image), that's where you got the -6.5
SO it's between 2 and 4 with gasket. I think I am alright now. Thank you if that's all to know!

The gasket is irrelevant ! Whether you choose to have the gasket in place or not when checking the fuel level doesn't change the required level of fuel as witnessed by the sight-tube. Or..... imagine if your gasket was a 2"" spacer, the fuel level must still be it's relative height to the jets & towers. The bowl ( C/W 2"' spacer) would simply hold more fuel. 6.5 to 8.5 is always measured from the bottom of the "Lip" or edge that surrounds the bowl flange. . I have referred to this as the base of the body but I can now see how that's been confusing.

Stan. Put your calipers on the LIP !

Oh yeah, of course. Sorry for being vague. My bad English! I meant 'visually', looking at the parts. But of course yes, the fuel level let's say 7.5 no matter what (ok, within that 6.5 - 8.5, but I will go by 'scotche's eye' )
My confusion came from the vocabulary. Edge, mating surface, base... etc... which was which? All's clear now
Cheers!

Oh yeah, and the lip!!!
Never ignore the lip! haha