Margie,
I just looked at the towels you are doing and they look like the same type of fabric that I am using right now,it is very thin cotton. this is only a suggestion, you might try using a basting stitch before you start your design to hold everything in place while the design is stitching out. When I do this type of towel, I use 2 sheets of Ann The Gran water soluble stabilizer underneath,then on top of that another piece of water soluble,I use the basting stitches at the beginning.This helps to keep the fabric from shifting. I do these the hoop-less method so as not to get hoop burn on the fabric, You have to be very careful when doing this type of towel and this method as they are so light weight they can easily shift, Once the basting stitches are there I don't think you will have as many problems with it, You can never over stabilize something,so if it looks like you are still having problems with it add another piece of water soluble under it. When done take as much of the waster soluble off before laundering or spritzing with water.
I hope this helps you out some and Good luck with them,
. here are some free basing frames for you in case your machine does not have them http://www.threadartist.com/embroidery_basting_frames_
Judy
Judy 
Help me to start each day with a new attitude and plenty of gratitude!