PS I also have some 4066 chips:
https://ics.nxp.com/products/hef/datasheet/hef4066b.pdf
The exact chip name is HEF4066BP
Would these be any better/worse to use?
it is what mr. stearns was using (the source of the examples you posted)
**broken link removed**
i can't see you needing much else really,
pins 5, 6, 12, and 13 of each chip would be connected to your arduino;
1, 4, 8, 11 to your common-bend-point; 2, 3, 9, 10 to your bend-points for example.
pin 7 to ground, pin 14 to your +5.
pin 5 controls the switch between 4 <-> 3
pin 6 controls the switch between 8 <-> 9
and so on and so forth.
everything else can be done in software right?
with 20 bends and one common point, you might get all kinds of weird interactions when using bi-directional switches, which i guess is what you want... might depend on what the common point actually is!
personally i'd try a potentiometer on that common point to see if it affects the effect