Taking the projector plunge, couple o Q's

The Viewsonic Pro8200 (less expensive), Benq w6000 (more expensive), and Panny ar100u (the one you mentioned) are generally the 3 main contenders when needing a light cannon.

The Pro8200 produces a better image IMHO, it has a smoother more film-like look and will be sharper unless you get lucky on the convergence of the Panny. I have never seen this specific Panny that I recall, but I've seen so many LCD projectors, and DLP is sharper and smoother with better pixel fill usually.

The Benq w6000 overall produces the best image of the three, but it's about $500+ more expensive, and it's almost as bright as the Viewsonic in some respects, and it does better blacks, and is a tad sharper. However, it is noisier than the VS, and it has more potential RBE (only if you are sensitive to it), but it also has better placement flexibility.

The Viewsonic needs to be ceiling mounted and you need 9' ceilings to do it easily (although you can get away with 8' ceilings potentially, definitely 8.5'). The Benq has a little more placemnt flexiblity over the VS, and the Panny ar100u has the most placement flexibility.

Any of the three will produce a decent image, but the VS has better blacks and contrast than the Panny pre-IRIS, and the Benq w6000 has darker blacks than both of the other two.

I think you are on the right track.

I did a lot of research on the AR-100U a while back when I saw a deal on them- I did find reviews and it seemed like an excellent projector for the price point. Definitely will be adequate with compensating for ambient light. Picture size depends greatly on the projector's distance from the screen (or wall). The manufacturer website usually has a calculator tool for that. You input the projector model, distance from the wall, and it will give you the screen size. Or you input the desired screen size and projector model, and it will give you the required distance.

I didn't get the Panasonic because they sold out before I was ready to pull the trigger.

I would stick with DLP unless you are RBE sensitive or need the extra placement flexiblity of LCD.

I just recently got this projector(ar100). Its great. I sit about 10' from the screen and the projector is right above our head, its little noisy, but Get 100" easy. Its not optimal, but I don't mind. I did get a nd2 filter to calm down the brightness with it being that close. I have a large window opposite of the screen to the right, with the vertical shades closed I get a good picture, a little washed, but watchable. Oh, and I use a favi 1.3 gain screen.