If your room has ambient light but not from the sides, rather straight back, those HC gray's aren't going to help that much, so you might be better off with a nice "plus gain" screen - say 1.3 to 1.6, to brighten the image. That won't help though if your ambient light is back where the projector is. Some HC gray screens are better at rejecting light coming from above, than others.
Whatever your room for the Epson Home Cinema 3010, I offer all, the same advice:
Should you be able to pull it off, darken your walls and ceiling, and if possible, also the floor of your room, to dramatically improve your experience. Keep in mind with a bright projector like this Epson, however, you can cut through quite a bit of ambient light when you want to watch sports, regardless of walls... 2000 lumens can go a long way.