Sew or Glue Soles to Fuzzy Feet Slippers

[losnana]

I purchased this
http://www.save-on-crafts.com/jifgripbrnon.html
to use as soles for my Fuzzy Feet slippers (http://www.knitty.com/ISSUEwinter02/PATTfuzzyfeet.html).
At first I intended to sew it onto the slippers, but after thinking about it, I am wondering if the thread will cut into the felted yarn. The directions state that it can be sewn or glued onto fabric. Have any of you used this before? What do you think?