I use Perle Cotton for Huck Embroidery. I have purchased them online from JoAnns and Herrshcners. Michaels sometime has them in the store. I use #5 also. I like the Perle because there are more colors available but you also might try crochet thread. #10 is the same as 5 and #20 the same as 8. The #5 in Perle is also available in smaller amounts and lots of colors and available at JoAnns and Michaels stores.