Guys, I'm working hard on pages on my website on heath & playing the bass guitar, hoping them to become a thorough study. A problem that struck me was the relationship between neck profile and playing comfort, or lack of that, creating health risks. Issues might be: C-shape, D-shape, asymetric shape, radius, thickness, on 4-string or on 5 and 5+-string. The most important question is how these shapes might relate to the positioning of the thumb. A critical factor is hand size. I'd be interested to hear about your opinions and experiences.