Your No2 method is what cinemas do - adjust the width to suit the aspect ratio by moving the side curtains.
That isn't always easy to do with a home cinema projector, but a HTPC will help because it will give you total control of the height and width of the projected image (if you use a program like YXY).
I use a 16:9 screen which is filled perfectly when a 16:9 movie is projected onto it. When I project a 2.35:1 movie, I use the HTPC to position the image where I want it on the screen, which can be at the top, middle or bottom. If you did this, and decide to (for example) always position the 2.35 movie at the bottom edge, you can then use some black cloth (like felt) or whatever to mask the unprojected top area of the screen. This seems to be the most common method here as far as I can tell.
f you want to keep the 2.35 screen, then maybe you will have to make a rail system so that you can move the pj back and forth quickly and easily to get the height of the image lined up, along with a two position release/fix mechanism (like a pin through a tube, or locking nut and thread) for height adjustment. You can then mask the unused side areas of the screen just like in a real cinema.
Originally Posted by elmalloc
Who says Cameron is "right" and why do we care about him so much - lol!
I trust Gary Lightfoot more than James Cameron.