Oh my, this is very intricate. There is a company called Gutermann that sell both silk and polyester thread. I have used both threads and find that the polyester is as soft and workable as the silk. It comes in spools of 33 meters each. The color selection is very good. I think this will be your best bet. I bought mine at a Joann's Store. I do not see the specific one on their online store. Amazon has some: https://www.amazon.com/Gutermann-Topstitch-Heavy-Duty-Thread-Poppy/dp/B000FKK2TY/ref=sr_1_4?crid=2M44KRGF43VC&keywords=gutermann+topstitch+heavy+duty+thread&qid=1569983397&s=arts-crafts&sprefix=Gutermann+top+%2Carts-crafts%2C198&sr=1-4

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I paid around $2.00 a spool for mine. If you have a Joann's near by it might be worth visiting.