I have done quilting in the hoop on my Janome 12000 using 100% cotton thread Essentials by Connecting Threads, since I had several dozen colors of that already when I got the machine last year. It works great! I've also used (quilting in embroidery hoop) Signature cotton, Aurifil, and Coats cotton (quilting). I actually don't recall what weight is the Essentials but I think it is thinner than regular sewing thread. Always make a test sample with your intended needle & at least start your design with samples of your quilt batting, to see if you can manage hooping it (or modifying the hoop) before beginning the entire quilt.