A bit late to this party, but I think you are definitely going to be happy with the projector and screen selection.
I remind people all the time that $20 in dark paint is a far better choice than a $2,000+ ALR screen. So, make sure you treat the room properly for home theater projection.
The screen size should be based upon seating distance and personal preference. So, I recommend that if you can, try some different screen sizes before you actually buy a screen if you can. You may find 120" to be smaller than you actually want. But, the Epson certainly has the muscle to go larger if you want to.