Glad it was a little helpful!
FWIW should others read this info, the weird nut goes on the threads first (flat side facing away from the switch) followed by the spacer washer with the tab stuck in the groove of the threaded housing, then switch get slide into dash panel from back side. Once in the dash, see how much the exposed "bezel" thread is and adjust the inner nut to reduce or extend the number of exposed threads to be just less than the depth of the "bezel" nut. Finally, install the "bezel" nut to lock it all into place.
Done this way, there isn't a need for an added spacer. Glad your solution worked out just fine!
Dan
