Hi Mike,
I have a 6 string Europa with the comfort taper that I measured. You will want to know what NOT to get if you want a custom narrow taper. Here are the dims:
Neck / fingerboard width:
Width of nut: 2.215; width at 12th fret: 3.060; width at 24th fret: 3.515
More importantly here are the average string-to-string measurements (spaces between the strings measured from string center to string center, then averaged):
Nut: 0.370 Bridge: 0.714
I find this bass string spacing to be rather wide for my right plucking hand, and although it may be good for some techniques, it seems a little too wide for me in general. I sometimes find I miss a string because my fingers have played the classic taper or something closer to it for many years. The neck pickup is also right where I like to slap so it gets in the way. Both things are minor, and can be worked with if I didn't have a few other basses with different tapers that I like to play all the time. Hope this helps you identify the exact taper you want.
Kris