Thank you so much for your input! I have three spools of rayon (Sulky viscose, which is rayon) I bought before I read that rayon sometimes stretches and is problematic, so I was wondering if I should return those. If it fades and doesn't wash as nicely as poly, I think I may return those spools. Today I have been playing around with appliqued hearts, using Coats and Clark polyester thread, and that is stitching out well. I'm having a blast. Already made three beginner mistakes. I think I'm going to discover all of them in Lesson Number One, lol.