I'm building a partscaster with 2 x P90's that is controlled by a 3-way blade switch. In the middle position, I'd like to have both pickups together, but with an independent volume pot for the neck so I can control how much of it is mixed with the full on bridge pickup. Both pickups are then controlled by a master volume and a master tone.
Since I'm using a 500 Kohm Master Volume and a 500 Kohm Master Tone, what kind of volume pot should I be using the the independent volume of the neck pickup in the middle selector position?
My guess is 1 Mohm because I want to preserve the original tone of the neck pickup as much as possible since treble is already leaking through the Master Vol + Tone pots. However, I don't have the experience to know if this is a good idea, so any help would be appreciated.