1.  Once you have set up the Display options to the staff preference, use the Epson remote.

2.  Scroll down the Menu until you can see the ASPECT section

3.  Select 4:3 rather than the default "Normal"

Now you may have to make fine adjustments but this has produced satisfactory results on the M1 Macbook Air screen and also the projector image filling the SMART Board as much as possible and makes it easier to view.