I have produced a PCB and built a new delay using the PCB and the original schematic. The results are gratifying. I did make a couple of minor adjustments. The board is designed to fit in a 1590b stomp box. It draws 20mA so it works pretty well on a 9V battery.
R12 – changed from 33K to 39K
R2- changed from 56K to 47K
c19- changed from 2000pF to 2200pF
c16- from 247pF to 300pF
Video Demo Here: