Yamaha RGX 121 FP - Wiring advice required

Hi,

I've not played in years and have been given a Yamaha RGX 121 FP.
It's a decent little guitar to start out on (again), but it's missing the tone pot.

Does anyone know which pot I need to buy (and IIRC a cap too) and how to wire it up?
I have soldering skills.

An image of the wiring as it stands can be found here:

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Thanks in advance