Some "proof" that weight does not matter on flat, steady speed roads - the Lotus superbike from 1996 which set many a world record in the day was a portly 8.35kg (18.41lb) which even then was heavy for a track bike (even road for that matter). But this is a track -no sidewinds, hills and acceleration save for the initial ramp up.
https://www.bikeradar.com/us/road/ge...ort-110-41260/