Theater build.. 19' deep, 17' wide .. need help on projector, screen etc , pics

see my thread in dedicated home theater.. I'm completely open to screen manufactures- my 3 speakers will be a tight fit behind the screen on a sound stage-- i can move the screen up and down on the wall-- but the wall follows a vaulted ceiling and has a 81.5" total height-- the back end of the 19' room has a 103" height -- there is a sketch that shows the calculations of the screen height / seating height/ projector height..

I'm thinking a 100" screen-- thats what is sketched up-- here is the sketchup file if you want to take a looks http://www.megaupload.com/?d=BX8CSUHB

can i go bigger?

here is the screen viewing distance from the 2 tiers of seating -- 11ft and 17 feet-- should i go with a bigger screen?


here is the back wall measurments of imaginary line of the top of the screen (100")





link to the build thread
http://www.avsforum.com/avs-vb/showthread.php?t=1287888

and a butload of pics

nice read-- so i should hold my speakers back 1 foot from the screen? whats the minimum.. or should i just forget about doing the speakers behind the screen and build them into the millworks.. Perhaps dennis will tell me that when we order up his service..