I use my ruler, mat and rotary cutter also.If it hard for me to make accurate cuts by cutting only two thicknesses of fabric so I fold the fabric in half with the cut ends together so I can cut for thicknesses and that seed I up. If I am just cutting strip from many fabrics I layer at least three fabrics together, sometime even four fabrics. I the rotary blade is sharp you shouldn't have any trouble cutting eight layers.