I found when installing them on my G450 that if you install everything loose then slowly work your way around tightening everything gets pulled into place. This was with CR High bars - whatever brand HDB sells.
Stock bars? Could be the bend that makes it a little more tricky.
A set of these are going on my F8GS next time I bent the barkbusters beyond repair.
If a man does not keep pace with his companions, perhaps it is because he hears a different drummer. Let him step to the music which he hears, however measured or far away. -Thoreau