Hey Matt,
I finished up a guitar bouzouki last year too. I used Graham McDonalds book, but built it very different. His book shows a 34mm nut and a 44mm between middle of outer strings at the bridge. I made mine 36mm at the nut(36mm is the width of the nut, not the outer strings) and my bridge outer strings are 47mm. This seems to work great for me. The string spacing between strings at the nut is: (GDAD tuning) G strings 3.5mm in from nut edge, 3.5mm between strings, and then 7mm to the D string. Then the D string spacing is 3mm between strings, then 6mm to the A string. Then 2mm between the double A strings, and then 5.5mm to the high D. 2 mm between those strings, then 2 mm to edge of nut. Let me know if you need the bridge spacing too. My hands are getting tired
Forgot to mention that this is for double strings as opposed to octave strings on the low G & D.
Tracy