String Spacing
Probably the most common uke nut width is 1-3/8" (35mm) with 9.5mm string spacing. If you go 9mm spacing for 5 strings, that yields a nut width of 42mm or 1-5/8". This is still much narrower than a typical guilele neck of 48mm or 1-7/8", so it sounds logical. But.... measuring my guilele, the string spacing is very close to 8mm, not 9mm, and I'm liking this tighter spacing on the 6 string.
So that was the initial plan - 8mm string spacing which yields a nut width of 38mm or (wait for it) 1.5".
I have to admit this gives me a little pause since probably the second most common uke width is 1.5". But that is for 4 strings, and here we are talking about putting 5 strings in the same space.
We've decided to split the difference and do 8.5mm spacing and 40mm width. Still time to change my mind, but that's the going-in plan.