I was thinking about a metal ruler too! I don't want my dd to say, ok mom, lay off of cutting the ribbon! She didn't like my glueing onto the clips, until I got the double sticky tape, now she lets me! lol
Thanks gals for helping! Now I need a bigger piece of glass, so my metal ruler fits on it!
Anymore ideas, I would love to hear about measuring. I thought about putting a piece of paper underneath the glass with 4.5" market all the way across it, but would love to hear how others are doing it!