Hi there! I find the thumbrest extremely useful. I couldn't feel comfortable without some support. I didn't find enough of that when resting my thumb on my Fender JB's pickups. So I have the thumbrest sold by Fender installed above the neck pickup, forming like a "T" shape with it. I know Tim Commerford got custom made thumbrest on his basses. I'd like to know your thoughts and experiences on that. Cheers!