Final update:
I changed C7 (tant), C8 (film), R18, R21, VR2, VR3, added R23. 78L05s can be a little noisy and R23 kills the noise. C4 can be 22nF or 33nF. 33nF adds a little more midrange when BRIGHT is turned up. With compressors, it's a trade between speed and distortion. Fast ones can make distortion and low distortion ones have a slower attack. Setting RELEASE below noon will produce some distortion on the lower strings, but the initial pop when SUSTAIN is dimed has been minimized. Not a bad compressor, but not as good as the Delegate IMO. Next up: one more look at the Thumbsucker.