Previously Alt + Tab always went to the previous screen. It makes perfect sense as that is what it used to do. So Alt + Tab can toggle between two particular screens by always going to the previous...

Yes that is what I am trying to do

Since switching to Windows 10, Alt + Tab does not toggle to previous screen in a number of case, i.e. you have to hit Alt + Tab twice to go to the previous screen or go through the thumbnail screens....