Stop the presses... another Noob seeking advice!

My choice would be the Da-Lite Perm-Wall 119" diag with High Power fabric (Model 79915). That would provide a nice, bright image for your RS45 that will be especially welcome if you watch any 3D. You'll need to mount your pj close to eye level to maximize the gain. You can contact Da-Lite and request a sample to see how you like it. Mike Garrett or one of the other AV Science sales folks can give you a quote & would provide good support after the sale if you run into problems.
http://www.dalite.com/products/product.php?pID=96&cID=20

Check out the first page of the High Power thread if you're unfamiliar with this material. (The early part of the thread discusses a 2.8 gain fabric that's no longer available. The newer HP 2.4 fabric is very similar however.):
http://www.avsforum.com/t/773065/high-power-a-review-part-1/0_40

A bit off-topic, but if you have a few bucks left over after your screen purchase I'd recommend also picking up a Darblet. That would provide another nice bump up in picture quality for your new home theater. Darblet prices will be going up in a couple weeks so order soon if you're interested.
http://www.hometheater.com/content/darbee-visual-presence-darblet-video-enhancer
http://www.avsforum.com/t/1399154/darbee-vision-darblet/0_40
Edited by henrich3 - 8/25/12 at 8:13am

Stadium seating should not pose a problem for the HP. Take a look at the graphic labeled "Retro-Reflective" in post # 1 of the High Power thread. The audience heads need to be under the light path shown in dark yellow. Now imagine that graphic showing two rows of seating, the back row slightly elevated. Both rows of the audience can still receive the same gain by adjusting the projector & screen height. It's not critical to ensure that both rows are identical distances under the light path. If one row of heads is 18" under the beam while the other row is 24" underneath, the other row will have slightly less gain. No biggie. Viewers in both rows should still enjoy a significantly brighter image than they would on a matte white.

I'd recommend that you request samples of HP, matte white, and whatever other fabrics interest you before you pull the trigger on a new screen. Seeing the differences for yourself should help with your decision. Da-Lite samples are typically ~ 7". They will send out larger sample sizes on request however. Ask for an 8" x 10" or there about to better judge the material.