Hi 8lueoval,
I don't think that these handle bars have been extended for a tall person at all, rather it's because when the new engine was fitted the bars would clash with the petrol tank and thus they have to be laid right back then extended to get to the height of a normal sized person. These solid deck series 1 Scotty's originally had Kirby power plants fitted and the tank was at the front thus there was never a clearance issue, it was only when SB changed over to the Briggs line up of engines during Series 2 production that the handle bars were totally redesigned to clear the large rear mounted tank fitted on the 3 Hp units.
Without a doubt the series 1 was the best designed unit for the 20 inch size machines as they had less flex in the chassis while just about all the Series 2 twin railers suffered from rail fatigue and require repairs. Luckily you shouldn't have these issues with your machine.
Cheers,
BB