I posted this earlier on another thread and thought it might deserve it's own thread. As I've stated before, I haven't used flat picks much at all for most of 40 years, but I have used thumb picks off and on extensively. Especially in my banjo experience. I have found several thumbpicks that work great for different styles and tones. BUT, I have never yet found one that works right out of the box. They all need to be shaped to your likings. I use Dunlops, Nationals, and Fred Kellys. I distinctly like the Fred Kelly speed pick for Acoustic guitar picking, but not strumming. The first thing you need is to adjust the shape of the pick. Cut easily with a pair of nail clippers, file with a fingernail file and smooth with 1200 grit paper. Buy a dozen and reshape until you find what works for you. Then resize to fit snuggly on your thumb, most can be shaped by soaking in hot water then bending. The last thing I do is rough sand the inside so it doesn't slip around my thumb. Seems like a lot of work, but they last for years. HAVE FUN!!!