How does 2 volume pots in series effect the tone?

I'm considering modding my Jazzmaster to make the rhythm switch into a series switch, which would leave me with 2 pots I can do something with. My first thought was to make them into individual pickup volume controls so I can blend the pickups when they're in series/parallel. I've only worked with Fender-style guitars though, so I don't know how stacking volume pots in series effects the resonant peak of the pickups. Also I'm pretty sure one of the rhythm circuit pots is 1M and the other is 50k, which makes this question even more important for figuring out what the end-result would be.

Can anyone enlighten me?

*edit* To clarify, I'm asking specifically about the effect of: single pickup -> dedicated volume pot -> master volume/tone pots -> output, NOT the effect of having individual volume pots on two pickups in series. I realize I wasn't clear about that.