I would cut the strips width of fabric. Random widths is best. I don't know how many strips you will need. You can always cut more but enough to cover the backing. It also depends on how many fabrics you use. You may have some waste but they can always be used in a string quilt. Sorry that I can't be more precise. I always just cut mine as I went along so then I could determine width and color as I went. I would cut the strips to fit. I know clear as mud. It will be really easy and fun.