This stuff gets more crucial to me now I'm playing 5's. It makes a HUGE difference to me.
I've found my comfort combo in an MPG Level 5 - 1 3/4" nut and 19mm spacing. It also has a semi chubby round profile. I have pretty small hands so it flies in the face of logical thinking that I wouldn't want the slimmest neck for comfort. Undeniable, nothing has stood up to it yet. I suspect the thinner flatter necks just seem wider in proportion even when the numbers are close.
I am on a quest to find other brands that have this, I've sadly ruled out some wonderful basses.

. I suppose I should feel lucky having found the MPG's.