Projector screen Help please

[minimo]

Hello to all, I just got a new projector (Sony HW15), and I have a question about the screens. My space has some ambient light, it is not horrible, but it is not pitch black either. You can see the space in my gallery. I put two new curtains to cover other windows, so it is darker than in the pictures. I was considering about getting this screen: http://www.nationalaudiovisualsupply...l?feed=froogle

But my question is about the gain in this screen. Is 2.2 Gain way too much for a semi controled ambient light room, or is it adequate?

Thank so much for all your help, you guys rock!!!!!