[sdiy] vocoder design questions

[synth at charlielamm.com]

I am thinking about trying to design + build one of these.  My goal is to
get the sort of sound a Bode 7702 has: to my ears, crisp, with good
clarity and low distortion and noise.  Hopefully without the Bode 7702
vintage sort of price.

Questions:

a) Most "pro" units I see seem to have 15-18+ bands.
Does anyone know (have a link to) the center frequencies of some of these
units?  For instance, the Roland SVC350 (18 band? um, 20 band?), Bode 7702
(16 band?)

(EG: I found the center freq for the MAM-11: 11-bands: 100, 225, 330, 470,
700, 1030, 1500, 2280, 3300, 4700, 9000 Hz)

b) What's the slope of these filters?  I see the Roland is 54db/octave
(steep, almost no overlap between bands, right? assuming I am reading the
web page right....)  Is this a design goal? I have seen some synth-diy
archival material saying overlap between bands may be good....is this
true?  For me, clarity is key....i.e., if my carrier is a voice, I want
the output to sound as voice-like as possible.

c) Anyone have links to the schematics or service manuals for some of the
classic designs?

d) Trying to have a low parts count I am sucked into the idea of using
MF10's or UAF42 for the filters (actually the UAF42 looks good because the
ext part could/would be very low).  Anyone done this?  Good idea?  Bad
idea?

e) What sort of bandpass filter architecture is commonly used?
Sallen Key?  Butterworth?  Does it vary?  Does it matter (I assume it
would)?

f) Same sort of idea as (d).  To cut down on parts count I'd use
monolithic quad VCA's like SSM2164.  Good idea?  Bad idea?

Thanks in advance for the help!