I will leave question 2 and 3 for someone with more experience with projectors.
Putting your room size into http://www.bobgolds.com/Mode/RoomModes.htm shows that it should be a good room acoustically. The only problem may be the seating location as you typically want it either at the front 38% point or the rear 38% point to get the smoothest response.
I am sure you will get some good advice from the other people here with regards to screen size.
Cheers,
Bill
Putting your room size into http://www.bobgolds.com/Mode/RoomModes.htm shows that it should be a good room acoustically. The only problem may be the seating location as you typically want it either at the front 38% point or the rear 38% point to get the smoothest response.
I am sure you will get some good advice from the other people here with regards to screen size.
Cheers,
Bill