Backing width issue
I have a throw quilt top that I made for my Mother for this coming Mother's Day. I wanted to send it to be long arm quilted to soften the straight edges as it is a mix of 2.5 inch blocks making up a pixel heart center and 2.5 inch wide strips. The top measures 51 W x 60L. I have a very nice older piece of Ralph Lauren brushed cotton fabric that is just over 55 wide but with the very wide salvage edges measures almost 58 inches. So in order to meet the Long Arm requirements I need 59 inches of width. So my question is what do I do to remedy this? Do I waste some ugly jelly roll strips and just piece them on the sides as waste strips? I really don't want to waste another full length of this fabric for a few inches--but also don't want something to happen and have the top get slightly crooked and then have issues. Any ideas would be great.
The pic is of the backing I would like to use. It is darker in the photo then in person.