I have both sizes and they're okay. I wish they were a bit wider because when I'm holding the handle, my hand is still in the way a little. I am confused about how it works on top of another ruler since the slippery-ness between the plain ruler and the fabric is the same either way. The slidelock has rubbery balls that would never even contact the fabric if it's on top of another ruler, and the other ruler is still slick on the underside.