I read with interest your methods for prepping terry towels for embroidery.  Ive had a lot of luck with the following method.  I steam press the naps and then  apply a piece of glad's press and seal front and back to prevent the naps from poking through my design.  I use water disolvable sulky as a stabilizer and hoop my towel.  When my design is complete, I simply tear away the excess and spray the back of the design/ towel with water mist to dissolve the excess stabilizer. No muss, No fuss.  I'm done.

Pat