650b conversion....what about 26 conversion?

If:

700 x 40c results in overall diameter of 702mm 650b x 2.3 results in overall diameter of 701mm (113% air volume cross section gain over 40c)

Then:

26 x 2.75 results in overall diameter of 699mm (205% air volume cross section gain over 40c) or 26 x 3 results in overall diameter of...