I like ripping off large pieces then starching and ironing before I cut anything. Ripping gives a very straight line to begin with...In your case, I would rip a small portion 2 or 3 inches off of one end and then work from that straight line to cut or rip your pieces. If you iron each piece after you rip it off you will get a better measurement to cut (I would allow a few inches extra for error on each rip.) Hope this helps...it is sort of like the measure twice rule...would not try to get an exact measurement on each rip.