I run 16/42 and that feels a good mixed size. For all the mountains around me a 16/45 would be nicer for the technical climbs but I wouldn't want the deceased range brought on by the lower fuel economy at highway speeds (120-130 kph)
Then again after going to a .5 clutch oil jet slipping the clutch for an extended duration isn't an issue with 16/42.
"All that is gold does not glitter,
Not all those who wander are lost;
The old that is strong does not wither,
Deep roots are not reached by the frost."
'12 690 Enduro
// 690 Wiki