I came across a similar situation just the other day with the HPF/LPF board. One of the values was blacked out and it looked like 1M and 2 x 2M2 resistors were right above it; after examining the schematic, I realised it was a 1k 'cause if it were 1M then no signal would get into the pedal as it traced back to R1.
What if you split the difference between 3k3 and 1k5, and use a 2k4?
It looks like Manfesto used a 1k5 in his build and it worked well(his review is why I wanted to build this). https://forum.pedalpcb.com/threads/cast-iron.20453/ If I don't hear differently I am going to run with that.