Vintage Synth Repair

I just bought a Polysix about three weeks ago; I'm really happy with 
it. It's in great shape cosmetically, every thing works as it should 
and when I opened it up, I saw to my great pleasure that the battery 
had already been replaced. A very clean and professional job too! 

Anyway, the only thing I don't like about it is that the mod wheel is 
assigned to the VCO depth and cannot be routed elsewhere. And I really 
don't like to add "a touch of vibrato" while I'm playing! 

How difficult a mod would it be to assign the mod wheel to the VCF or 
VCA depth instead?

Better yet, would it be possible to use the VCO/VCF/VCA switch in the 
MG section as a double duty switch to also change the function of the 
mod wheel? That way the mod wheel would always be assigned to whatever 
is currently selected for the MG section.

Thanks,

JF