I have a tooth lock washer that goes with the pickup selector on a Series bass.  Does anyone know if it goes on the top or underside of the brass plate?  Thanks.

I put it under the nut on top, seems to work well.

Dad's preferred arrangement: switch ---> toothed lockwasher ---> [mount on plate or wood]   ---> dress washer  ---> hex nut

Great, thank you, I will revise the set up