I have a room slated for a home theatre in the future and was wondering if anyone could direct me on the average throw ratios of front projectors. I want to have the electrician run signal and power cables through the ceiling during construction but am not sure how far back to put the outlet.

I have no idea what type of projector I will get yet but am figuring on an 8 foot screen. The room will have 9 foot ceilings and I realize I won't be able to get it perfect with so little info but I'm just looking for "close."

Any suggestions on what is typical?