If you don't use a woodburner or have something premarked for cutting ribbons, this may speed things up a bit.
Cut your ribbon in sections of 18".
Measure each ribbon to 18". Then fold in half, cut and you've got 2 ribbons at 9". Then fold both ribbons in half and cut again.
Voila! 4 x 4.5" ribbons ready to be heat sealed and attached to your clips.
You could also do 36" or 72", but not 54" =)
The idea that you have to be able to keep cuting in half repeatedly, to eventually get to 4.5". Minimizes measuring time