After having years playing 4 strings I got my first 5 string and discovered that tighter spacing is everything. Faster navigation, more comfortable, better on my plucking, the neck of a 5 being wider and fatter fits my hand better so it's helped me not get as fatigued from playing long sessions. The best neck for me is either a Warwick or Tobias. They both are great for my hand comfort. Ibanez SR is almost too thin but if I keep a fast action it's still comfortable. The tone is also super nice. But anyway my specs would be described as 16.5 or 17mm and 45mm nut. My preferred neck profile is a little bit flatter like a Warwick or asymmetrical like the Tobias. I have larger palms but shorter than average fingers. I think it has to do with why I like what I like. More room in the palm but easier access for the fingers. I never liked wide string spacing and I don't really care for the width of 6 strings.