Needle 2.64 position 4
Needle jet #46-241
Idle jet 45
Idle air jet dia 1
claimed 47.0 mpg @ 60mph (with a pointy headed anorexic midget rider)
This was the spec for a non US G/S with no polution control.
I think you must be getting pretty close.
I never could work out what they meant by position 4 as my needles only had 3 rings.
My bike is slow but the earth is patient.