Need help adding expression pedal to EHX Micro Synth Bass

[smallpoxchampion]

I have a ehx micro synth bass that I would like to add an expression pedal to control the stop frequency pot, I've never done any mods on something with smd components so i'm stepping lightly before i drill any holes. Couple of questions before I get started:
What kind of jack should I be using for this? Will a regular stereo jack work? Also, what's the best placement to drill a new hole? (see pics)
From what I've already read, this will work with an xpr pedal that has 100k linear pot.
Could anyone point out where the tip ring and sleeve connections go on the pcb?



any help with this would be greatly appreciated.