I cut my own strips and instead of making them 2.5" wide, I bought 1/4 yd of each fabric, so I cut my strips 3" wide. That 1/2" per strip add about 20 inches to the length of my quilt. It didn't add anything to the width.
A group of us made them together, so I could compare theirs (which they used 2.5" strips) to mine.