Roll Your Own
15V power modification
For 0-5V CV adjust R1 to 33k.
For 0-8V CV adjust R1 as close to 54k you can get.
5V CV modification
For 0-5V CV adjust R1 to 39k.
For 0-8V CV keep R1 as 68k original.
The A-100 technical page defines 0-8V for envelopes.
When the gain knob is turned up you can turn it down with negative CV.
Increase LED colouring
With the cost of more sound leakage at fully closed gain you can increase the effect from the LED limiters colouring of the sound by raising the value of R9 from 68k to 100k or more. Or maybe even replace it with a 200-500k trimmer wired between one end and the wiper.