The image below was supplied by Tony in a previous post. It is how Dumble implemented a strat switch. The way I interpreted this is that a 2nd mid capacitor is put in series with the mid capacitor that resides on the pre amp board. This 2nd cap is soldered to a mid pot that contains a push/pull switch. When you pull the switch the 2nd mid cap is shorted out. So you have 2 mid cap values to choose from - 1) both caps in series and 2) only the cap on the preamp board. Plus, you are not adding 2 leads to an additional switch. I used .047uF on the preamp board and .015uF on the mid pot. With these 2 caps in series you get .01uF (the humbucker setting). When you pull the switch and short out the 2nd cap you get .047uF (the strat setting). I am very pleased with the affect that this has on the strat OD tone. Note that I am referring to a strat with single coil pickups that are vintage spec windings.
What I am not happy with is the push pull CTS pot that I got from Stew Mac. There is play in the Pot and when turning it, it feels loose and cheap.
Can anyone suggest another source for a 250K push/pull pot?
Most of the others that I found are for PCB mounts or have tiny holes to solder to unlike the CTS switch shown in Tony's image below.