Point Well Taken from In Cahoots states that you can use Sewer's Aid on your thread if you have trouble with it breaking or fraying.
Also the book suggest trying an embroidery needle 80/12 or 90/14, or even a jean needle 80/12 or 90/14.
I use Sulky's 30 weight cotton to hand quilt, and I wax it.
Jan in VA