Gary,
I mounted my 16:9 screen using the suggested screen centerline height for a 4:3 screen (note were talking about the screen center here and not how far down the top of the screen is from the ceiling). Divide the 4:3 screen height by two and add the ceiling to top of 4:3 screen offset and this will be your screen centerline height, mount the vertical center line of your 16:9 screen at this height and your set. By keeping the vertical center of the screen where it should be you wont have to vertically offset the picture up or down from the default zero centering position later on during picture adjustments.
Once installed you can vertically compress/squeeze the 4:3 raster down to a 16:9 height. I setup my Dish6000 receiver for 16:9 display and set my HTPC to display in anamorphic mode and both display properly at this screen elevation without having to adjust the picture vertically off of the default zero vertical setting.
Make sure your back far enough to use most of the horizontal raster on the CRTs . When properly running in full time 16:9 mode you obviously wont use the full 4:3 height of the CRTs, however you will be using the full horizotal width of the CRTs.
Bottom line is that the vertical screen center height would be the same height from the ceiling regardless of whether it is a 4:3 or 16:9 screen. When you initially fire up a projector whose default settings are for a 4:3 image, that image will overshoot the top and bottom of your 16:9 screen by the same amount top and bottom, just squeeze the image down until it hits the top and bottom edges of your 16:9 screen, put your display sources into 16:9 mode and your set.
Hope this helps.
John
