I buy tearaway from my local shop in stacks of 20 sheets. There are many different brands and weights. Don't forget the water soluble stabilizer for the lettering. It keeps the thread from sinking down into the towels.
It will depend on the bobbin size for your machine. A chart that may give you more info.
http://www.thethreadexchange.com/miv...in-information
More bobbins here. My machines use the 13305 type. I use them in the regular sewing machine sometimes with good results too. You can even buy them in specific colors for free standing lace projects or wind your own thread.
http://www.allbrands.com/categories/...bbins-class-15