Well, you put the switch in the ON position first, then pinch the rubber cover to remove it. 
It takes some 3 full revolutions of the set screw to clear everything so it will slide out.
I couldn’t find a thin enough T8 to fit inside so I ground off the shaft until it would fit through the switch. Be prepared for something like that.
Also, be prepared to remove the coil spring in the base of the switch assembly, it looks relatively small but it goes into the base about a 1/4” and is LONG… lot of resistance right there!