Jeahrens,.. Honestly I don't think you do understand what I'm saying ... I don't suggest that's your fault, it's mine for not being able to explain it.
I will try one more time but don't worry if it's something you can't ever figure out...
I have a 16:9 pj and a 16:9 screen and I tend to set it all up easy like that.
When I watch a 4:3 movie, it's side boxed in the 16:9 frame so that it's not distorted.
When I watch a 2:35:1 movie it's letterboxed in the frame so it's not distorted. (Nevermind it's actually a 16:9 image that is letterboxed from the start.)
So, when I watch a scope movie there is no zooming, ... no lens manipulation.
Now,... hopefully you're still with me... When I watch such a scope movie I mask the black bars effectively making a temporary scope screen.
What I would like is an apsect ratio that would put all other content into that scope shape... no extra lenses so zooming ....
This may be impossible to explain though and I'm certainly giving up at this point.
Most likely, my next projector will work with the zoom method and that's fine... no problem... game over.