Help picking an LDR/Vactrol

[dcfvgb]

I'm building a Fuzzdog Crap-fi delay and thinking of adding a Parasit Studio mod board to wiggle the delays.

How do I figure out which ldr/vactrol to use? The delay pot on the Crap-fi is 50KB.

Schematics

 

[Aleph Null]

For 50k, I'd use a 9203 and a green led, maybe a yellow if green is too intense. You could also use an NSL-32 or VTL5C9, depending on how you plan to situate the LDR, the on resistance might be more important than the off resistance.