Setting up a new home theater. Three windows that will have blackout shades plus curtains. Walls will be a darker color (not black) matte finish so the room should have minimal light levels. I am trying to decide between a 120" and a 133" screen. Is the HD1000 bright enough for these size screens?

Next, I need a motorized screen as this will be a dual use room. Will a non-tensioned screen of this size be ok or is a tensioned screen worth the extra $$?

Next, screen type. The ceiling will also be a darker color but not black. I'm thinking a white screen should work fine in this type of room.

Opinions please!

After a bit more research it appears an 8ft ceiling with a 133" sceen may not work with this projector. ...

At that size you're going to need a good quality screen with a high gain in order to have that POP that everyone speaks of. A high gain screen will give it a more plasma like look.

Get a carada bright white (or brilliant white?) screen which has 1.4 gain. They are expensive but obviously it can be used with the many projectors you buy over the years so you have to think of it as an investment of sorts.

Tensioned screens are the way to go. All nontensioned screens I've seen end up with waves in them. This leads to light not being reflected back at you as it should be which results in a dimmer image. Plus it's just annoying as hell to look at.

I've tried all the DIY screens; painted a wall, built a frame with screen material bought from fleabay. I now have a "real" screen (tensioned) and the differnce is night and day.

The ceiling should be fine, mine is white. You may want to paint the area behind the screen a darker color. It makes the image stand out against the wall.

By the way, i also have the mits.

I would think the Mits could handle the size you're talking about. But that is just theory on my part. (I have an HD70 and the Mits is supposed to be much brighter.)
I have a 100" DIY (Doable board) screen with an Optoma HD70 shooting from 11.5 feet onto it. The HD70 is in low lamp mode and the brightness is just right. It was too bright when I first set it up but that was several hundred hours ago and the lamp has settled into a better brightness level, to my eyes. The blacks are also better than when we first started using the HD70.
We have a completely light controlled HT (Basement - no windows and no lights while watching.) The walls are maroon and the ceiling is a dark gold.

Start with DIY and move onto a store bought screen, if need be, you can't lose. Our DIY screen cost $15 for the Doable panel @ Home Depot (But 100" is the largest it'll make using one panel - 49" height) and about $10 for various support mechanisms. It really projects a great image and I used the surface as-is. I applied no paint. I did need to find a completely mar-free panel, which wasn't easy.

Good luck

My Mits projects on to a 120" Elite matte white screen with a 1.5 gain (supposed to be anyway). The room is 13 X 22 and the walls and ceiling are beige color. I only have a 7'9" ceiling height so to use a 120" screen I had to mount the projector to a thin piece of board directly to the ceiling. I also have about 1" of upward tilt on the projector so the screen is about 18" off the floor. You can (if you look for it) notice a slight (and I do mean slight) bow to the picture when watching a 2:35 ratio movie. The upward tilt has no noticeable effect on movies that fill the screen. The room is light controlled. The projected image looks fine and is bright enough (can almost be too bright with movies like Ice Age). The Mits now has about 300 hours on it and I don't see much difference in the brightness than when I first got it. You should be fine using the Mits with a 120" screen. I would have even gone with a 133" screen if my ceiling height would have allowed it.