Update: aegert on FSB has experimented with the circuit and has found that putting a low value cap like 820pf between pins 1 and 2 of the opamp really improved the pedal. He also suggests that a 500K log pot is much better for the Gain control, so give that a go.
Update 2: daz at FSB has corrected some values from an original pedal he examined. New vero layout below, and it may still be worth adding that 820p cap between opamp pins 1 and 2 to see if there is still an improvement. You can also try something lower like 47 to 470p if the 820p cuts too much high end, or socket and swap to taste maybe.
