Both boxes you mention are pretty small, and do they come with a backrest pad? If they do, being that narrow, the pad wouldn't be very comfortable. She won't want to be leaning on the box without a pad. Personally I'd save up for a better box. I bought a Givi V47 from Motostorm.it with the pad, mounting plate, and LED brake light kit for just under $300. I bought the Kawasaki rear rack though. I want to figure out a way to haul my bicycle on back, and it just seems much more sturdy/robust than the Givi one you mentioned above.