Thanks. That looks like it should work. I guess that Cooper's plate should work?
Intermatic's information seems to indicate that they can be made to fit toggle or decorator style:
Box fill is something that I am aware of as a concept only. My understanding is that it is not dependent on, in this case, the switches that are used, only the cable or wire connections in the box. Please tell me if I am wrong. I also understand that even if box fill is not exceeded, I might still not be able to fit what I might want into a particular box.
If I am correct, in my case if the electrician that did the current installation did his job, I can change switches with abandon, as long as they fit.