I've made 100's of these and what I do to keep them more stable is...when doing the top stitching after turning right side out...I go from dart to dart in the bottom of the bowl. I haven't tried bamboo but sounds interesting. You'd want to be sure there is nothing synthetic in it. Please also keep in mind that Warm and Natural has 12% polypropylene so don't use that. Joann has a product on the bolt that is 100% cotton NO SCRIM. I use two layers of that...one on each piece of fabric and it works well.