When I do towels I have to make my tension setting lower, because of there thickness. Is your topping a thin one. Most topping is thinner then the one that we use on the bottom. Your needle size is fine, however, you maybe need to change to a new needle. H&*

I always use a size 10 or 11 needle, use the thin plastic type wss on top (20 micron) and a cut away stabiliser underneath.

No, not any problems, I´m using needle 80/12

I have never tried the plastic wss so I can't help with that. I always use vilene on top and bottom.

No, never had any problmes with solvy, but it is cold now and sometimes the wss feels too dry.***

I would first change needle.I usually use 90/14 needle. I use solvy clear Wss or Vilene which ever I have at the time. I use a med wt. cut-away on back because I have found after numerous launderings it still supports the stitching well. I would also try a different thread if changing needle did not help. I seldom hoop the Wss but use a basting stitch to hold towel & WSS to stabilizer in hoop. *

You might want to try slowing down the stitching speed. I use the clear type WSS on top and cut a way on the bottom.

What are you using on the bottom? Maybe the bottom stabilizer is breaking down. I have had the same problem.

I use the plastic all the time with no problems, I use a med tear away, I then pin my towel and plastic.

My brother machine does not like sticky stabilzer and the cotton keeps breaking. No problem with solvy on top.