The drawing in post #20 is not what I was suggesting!. The additional switch, S3, would connect the two wires that tie switches 1 and two. That will force the light to be on no matter what position either one is in.
The price of a UL approved rotary selector switch, suitable for permanent house wiring, would be quite a bit. And it would probably not fit in a standards single electrical box.

 

The drawing in post #20 is not what I was suggesting!. The additional switch, S3, would connect the two wires that tie switches 1 and two. That will force the light to be on no matter what position either one is in.

I thought that was the idea?

The price of a UL approved rotary selector switch, suitable for permanent house wiring, would be quite a bit. And it would probably not fit in a standards single electrical box.

I never claimed t would be inexpensive.

OK, you submit a diagram?

Ron