Heres one I am doing on my old Washburn Strat which I will finish over the weekend … the text below is not mine.... instead of the volume DPDT switch I have used a standard mini one but mounted it so that you only see about 4mm sticking above the pick guard through a tiny slot and is geographically situated between the volume and 1st tone pot, easy to find and out the way.
“ I installed the Kinman pickups with a Volume DPDT switch. When the switch is pushed up, the first position of the 5 position switch plays the neck pickup in series with the bridge pickup. The next position plays the neck and middle pickups in parallel with the bridge pickup in series. Middle position plays the middle pickup in series with the bridge pickup. All pushed-up positions use the bridge tone pot, which uses a .01uf cap. The nonstandard pickup configurations are great with more presence. “