I have to admit I'm a little paranoid about that calculator. It uses (almost) the same numbers as the x1/4800 calculator, and you have to wonder if they just stuck those numbers in until they can update it. The initial spec sheet for the 4805 was a quick cut and paste, and was loaded with inaccurate specs.
Does anyone know if the 4805 does in fact uses the same lens as the x1/4800?
"The projection calculator will be different from the X1's due to the larger horizontal size of the DMD. The throw ratio of the 4805 is 1.77-2.13:1 (distance to screen / screen width)."
If I'm calculating correctly (and there's no guarantee of that), the x1 has a throw ratio of 1.89-2.27:1. That means that with the projector 17 feet back, the X1 will have a screen width (on 16:9 material) of 89.9" to 107.9", while the 4805 will have a screen width of 95.8" to 115.3".
This also means that I'm not going to make definite plans on projector placement until the thing is actually available!