I have used a Kooiman thumb rest that I got for $30 from Forrests for several years now, and I can recommend it highly. What a relief over the original. I even tried a “Dutch Thumb Rest” that was a complete waste of money because it was hardly any better. With the Kooiman, I can play for hours without my thumb bothering me a bit., For $30 you can’t go wrong. And it even fits into the same screw holes as the original!