Having sconces on each side of the mirror will illuminate your face better than a light over the top of the mirror, which may be important with a make-up area. However, if your heart is set on this fixture, I would go with the larger one for a more even distribution of light and to fill out the width of the space a bit.

Honestly, I'm not big on make-up and will probably use a small self-lit magnifying mirror. Just care about the aesthetics for the vanity!!

Since it's in the corner I'd go with a bit narrower mirror and smaller light..but then I'm traumatized from the measurement mistakes in our remodel..these drywalls sometimes end up being an inch or two closer than they should...))

Or are yours built already?

It's also better to have a flexibility for side lights if you decide on them later at some point..not only because of the make up, it's just more flattering..usually..

aprilneverends - I am going out there this weekend to get exact measurements. The drywall is up, but I am guesstimating here.... Btw I've just been traumatized by the realization that I will have to order a tub about 6" shorter than I was planning - I totally get what you mean about things shrinking from the drywall!

Yeah, yeah..narrower vanities, the tubs that have to be switched..)) To get the exact measurements is a great idea.