|I do so love these kinds of body shapes.|
Top six are tuned like a guitar: E-A-D-G-B-E. Bottom three are like a 5-string bass: B-E-A.
Specs for 4001 Rickenbacker
Body Type Solid
No. Frets 20
Scale Length 84.5 cm (33 1/4'')
[b]Neck Width at Nut 41.3 mm (1 5/8'')
Neck Width at 12th Fret 52.4 mm (2 1/16'')[/b]
Crown Radius 25.4 cm (10'')
Body Wood Maple
Neck Wood Maple
Fingerboard Wood Rosewood
Weight 4.5 kg (10.0 lbs.)
Overall Length 114.5 cm (45 1/16'')
Overall Width 33.7 cm (13 1/4'')
Overall Depth 31.8 mm (1 1/4'')
Neck Binding No
Fret Marker Style Dot
Standard Series 1 11/16", Low Profile since the early 90's, 2012 and later D-18 is an exception
Vintage Series 1 11/16", Mod V shape always, HD-28LSV was an exception at 1 3/4"
GE/Marquis Series 1 3/4", Mod V shape always, no exceptions that I can recall right now
Authentic Series 1 7/8", 1 3/4", or 1 11/16" depending on which year the guitar is based, mostly larger profiles with subtle or no V-shape
Also remember that bridge spacing typically changes along with the nut size. Normal pairings are 1 11/16" with 2 1/8", 1 3/4" with 2 5/16", and 1 7/8" with 2 3/8". There are some exceptions.
Most seven- and eight-string guitars also have a larger, flatter radius than a standard six-string guitar. While a vintage Tele’s 7.25-inch radius may seem perfectly fine (especially if you just play open cowboy chords on the lower frets), on a wider seven- or eight-string neck it will seem absurdly rounded. On a wider neck, even a 12-inch radius will have noticeable curvature.
Choose your two scales (get the fret placement from a fret calculator like the one at http://www.stewmac.com/FretCalculator, or you can calculate it yourself too.), and decide which fret will be your perpendicular fret. I like fret seven most of the time but it depends on the scales you use.
Then lay out your frets from your perpendicular fret, but be sure to lay them out along the string center lines for the high and low E (not the edges of the fingerboard). Remember to factor in your bridge offset too when placing it and you are done. Then it’s a matter of very patiently and accurately sawing each fret by hand.
Neo-Reimannian theory is more complicated than I'd hoped.