I think it also has to do with the radius. From what I feel like has been my experience; flatter necks with narrower spacing kinda fee close to wider necks with a more rounded radius. I know that C, Slim C, and D, etc. is also part of it, so this is all with that not withstanding... I busted my fretting pinky a couple years ... ... more

For me it's neck depth as well as width. I need a neck that's between1.625 and 1.75, but a relatively shallow neck is essential too as is around 19mm or more at bridge. Some folks can be comfortable on anything, but after 25 years I've stopped fighting what feels right to me. ... more