Need advice for d.i.y. screen

[HDJK]

If Dezi or anybody with experience could help me out with the following:

I'm about to build my own screen (once I'm done I'll get a Sanyo PLV Z2000) and I'm still undecided on two things.

- Constant height or not

I don't have the money to get a projector that can support an anamorphic lens right now, so I'd have to manually zoom the picture in and out. Since I've never had a projector: how much trouble is it to zoom the picture and adjust focus?

By going CH I could make the screen wider (height is an issue at my place), so that would be a plus. And masking is easier on the sides than on the top and bottom (I was thinking of a dark curtain for masking).

- 21:9 (2.33:1), 2.35:1, 2.40:1

If you buy a screen, some offer masking for 4:3, 16:9 and 21:9 for scope. For the sake of convenience I'll use the metric system for my calculation; so if I make a screen that is 1 meter in height, what would be the best width? 21:9 would suggest 2 meters and 33 cm, 2.35 obviously would mean 2 meter and 35 cm and last but not least there is the option for 2 meters and 40 cm.

What is the usual approach for this? 3cm to each side is quite noticable with a white screen. So should I go for the golden middle and just crop off the sides when watching 2.40:1? Should I go for the widest and crop off the top and bottom when watching 2.35:1?
Now of course I can just use the zoom for each change and use the curtains to mask the couple of centimeters (never mind that this would be sort of annoying), but what if you use an anamorphic lens? I kind of want to build the screen for many years to come, and I might upgrade the projector some day...

Any help on this matter is greatly appreciated