Can I Place Polk T50 and T30 as LCR behind AT screen, if yes then
1. what will be the distance from AT screen and wall.
2. What will the positions of all three in terms of distance and orientation.
Being rear ported, the speakers need a little room to breathe... are you planning a baffle wall?
flat against the wall or tucked into a cavity will not be ideal.
Why limit the AT screen to 120" in a 11' wide room... can you go full width? 120" screen16:9 will be 104.5x44.5 for 2.35 (113.5" diag) and 104.5x58.75 for 16:9
Do you have these speakers? Can you consider some other ones more suitable for the purpose?
Apart from being too large to place against the wall, floorstanders may not also look very nice half hidden behind the screen .
Bookshelves will be best.
What height from the floor do you plan to have the screen? What's the planned subwoofer location?