I use Gutermann. I haven't used YLI, but if too thick is a concern...I used Gutermann all natural cotton 50/3 wt. to quilt my last project, it wasn't a bed quilt that may be washed a lot, but I liked the way my hand stitches looked with the thinner thread. JoAnn's has Gutermann and I buy it on sale or use a coupon...the thread has worked well for me and the ridge along the spool ends is great for securing your thread between cuts.