So 132mm will be fine. I need aero bars to fit my roof box. Not sure how I will get the stuff in and out of it lol
It is a stretch getting stuff in and out but okay if you're using the step on the sliding door side.
I always put my box in the middle of the roof too because the bags are so heavy lol (4 kids!) and I worry about the balance, but if you put the box to one side that would make it a little easier as well.