Hey guys. Newbie here looking for a projector for my church youth room. I am looking at a Viewsonic PJ558D. The room has alot of windows, and that concerns me. Also has very bright lights within the room. Will mainly show internet videos (like youtube), slideshows, powerpoint, and the occasional dvd through my computer. I have an 8ft screen. Should I be more concerned with lumens or contrast? Any suggestions or comments apreciated.