2.35:1 with Sony HW50

If you want Scope because that is the majority of you watch, then go Scope.
Sure start with zooming as you can always add an A-Lens later if required.

The Sony does not have lens MEMORY, but it does have lens zoom. You just need to manually adjust each time using your own skills

An anamorphic lens would work great with an HW50, as it has the necessary scaling modes.

Hey guys/gals, I wanted to know will I run into any issues using the Da-Lite High Power 166" 235:1 with the Cinevista lens with the Sony HW50ES?

I know someone in the UK who has bought an Isco II lens to go with his VW50ES after borrowing mine to try it out. He seems very pleased with it and he has (I think) a 4 metre wide 2.35:1 screen which is painted drywall. Search on AVF for 'Jagdeepp' to see his setup.

No issues unless you fall outside the throw ratio and distance guidelines for the CineVista itself. As discussed above the HW50 has all the necessary processing to make the CineVista look its best.

I actually recently reviewed that hardware setup, though with a 122" Screen Innovations screen instead of the Da-Lite. 166" is getting pretty large, but the Sony is very bright, and even in high power mode it is exceptionally quiet. Anyway you can read the whole thing here http://www.hometheaterhifi.com/video-accessories-misc/video-accessories-misc/affordable-anamorphic-system.html and see if that answers your questions.

If you watch 99% movies, then it may not be worth spending the extra on a lens just so you can swap between aspect ratios faster.

Obviously, some movies will be in other ratios like 1.85 and 1.78.

I would just buy the screen first and see how it goes manually going between the ratios. Take it from there.

You might not even need masking...see how you feel about the side black bars, which will be fairly black given no light will be projected on them, considering the projector is 16:9 natively.