I am working on final design for my HT. There's a link to a detailed thread in my signature if anyone has detailed questions. One of my current hurdles is projector placement and screen size. Using a THX frustum, I calculated the ideal screen width for a 2.39:1 screen at 11' 6 1/4" (138.25"). I had planned to use the Panasonic AE-3000U projector to attain the claimed "poor man's" CIH setup. But after using some projector calculators to determine the best ceiling placement, I am starting to question whether that projector will be bright enough. Any thoughts?

Now that I am home, I can measure the current sketchup model. It shows the following "optimal" screen measurements:

2.39:1 diag: 12'6" (150")
16x9 diag: 9'8" (116")
View distance front: 12'
View distance rear: 18.5'

The room is light controlled. I imagine it will be completely dark for any 2.39:1 viewing. I would like some active lighting for 16x9 viewing (meaning gaming / computer work).

Now that I am home, I can measure the current sketchup model. It shows the following "optimal" screen measurements:

2.39:1 diag: 12'6" (150")
16x9 diag: 9'8" (116")
View distance front: 12'
View distance rear: 18.5'

The room is light controlled. I imagine it will be completely dark for any 2.39:1 viewing. I would like some active lighting for 16x9 viewing (meaning gaming / computer work).
you will be fine. i leave the lights dim while watching movies its plenty bright.

I have the exact same setup you're wanting to get. I went with the Carada 1.4gain brilliant White screen and the Panasonic pt-ae3000. The screen is 55" tall and 132" wide-143" diagonal, 2.40:1 aspect ratio.
I was a little hesitant until I saw a user on these boards named Jamis. Look him up. His theater is amazing and he has generally had good things to say regarding the panasonic's brightness and overall quality.

Sorry for not giving you the link, I'm replying from my phone

Thanks for the input. If it makes a difference, I need an AT screen. I was planning to DIY one. Makes me happy to hear a few positive statements that brightness will not be a deal killer.

Sorry for not giving you the link, I'm replying from my phone
Here is Jamis thread (http://www.avsforum.com/avs-vb/showthread.php?t=794089&highlight=jamis).

My room is 13' W x 19' L x 10' H. Using a 103" Elite Cinescope screen with 1.1 gain. Front row is at 11'. The Panny is a great projector. I'm one of those "poor man" so it was a great fit for my needs.

The only negative thing I have discovered is that if you cannot place the projector within or close to within the frame of the screen, you will have to angle the projector downwards and use keystone if you want to take advantage of the zoom memory. I had no choice. My projector cannot be lowered any further because of my rear riser. My head almost touches the bottom of the projector when standing on the rear riser and I'm 5' 11".

It still looks great, but I would have rather had it level and not had to use keystone at all.

Does the keystone feature degrade the picture in some way? I'm planning to have the projector hidden inside a soffit, so having it angled is not a big deal. Having it hang way down into the room is.

Anytime you alter the image, you will "degrade" the picture quality. Not sure how much is noticable though.