The right answer is what works for HIM with HIS projector. He needs to buy it, set it up on a white wall/sheet/cheap screen, and see what subtended field of vision works for him. Preferences vary and will change when he gets used to thinking of his setup as a small movie screen instead of a large TV.
At 16:9, most home theater people would suggest sitting at 1.5 screen widths which translates into screens
112" wide at 14 feet to 128" wide at 16 feet
128 and 146" diagonal respectively.
3 heights seems a better number With a 2.35:1 constant height setup using an anamorphic lens
131" x 56" at 14 feet to 150 x 64" at 16 feet
Since this is too big for the Sony's light output, he'd do better sitting closer to a smaller screen.
We often sit 11' from a 87x49" (100" diagonal screen. While about right for most DVDs at <= 1.85:1, good scope transfers are too small. This matches the subtended field of view you get in the last row of a commercial theater meeting the THX recomendations.
At 16:9, most home theater people would suggest sitting at 1.5 screen widths which translates into screens
112" wide at 14 feet to 128" wide at 16 feet
128 and 146" diagonal respectively.
3 heights seems a better number With a 2.35:1 constant height setup using an anamorphic lens
131" x 56" at 14 feet to 150 x 64" at 16 feet
Since this is too big for the Sony's light output, he'd do better sitting closer to a smaller screen.
We often sit 11' from a 87x49" (100" diagonal screen. While about right for most DVDs at <= 1.85:1, good scope transfers are too small. This matches the subtended field of view you get in the last row of a commercial theater meeting the THX recomendations.