Hiya Simon
You from UK?
Only guessing as you say you passed your test, guys in the US seem to be able to ride without doing a test ...
As for the riding position, I'm 6'0" and don't have problems - guys in the UK who are taller also don't mention it - possible that as you're new to the bike (and riding?) that you might just be tensing your shoulders some?
Just my £0.02 worth.
I know that when I rode the T100 I had after passing my test, I relaxed quite a lot after just a few ride outs.
The arms out straight position is different if you passed on, say, a 500 for your direct access.
Good luck and welcome to the site mate.
(BTW, if you are from the UK, 'Dent' will soon get a mention .....

)