Thanks for the quesitons. I think this should answer all of them, but please, by all means - keep them coming!!!!!!!!!!
1.) It's multiple use. That's why the throw distance has to be flexible - the 4800 has an 8' throw distance as its minimum, which is key.
1.a) There's a home/home-office use, which includes movies, and that's an important function. But not only - it's going to replace my computer screen entirely, in part because of an eye condition which makes reflected light MUCH better for me than radiated screen light. There's some sports watching, but less important than movies. By the way - why would watching sports have different requirements than watching movies? I don't understand that at all - enlighten me, please!
1.b.) We also want to use it for events - we run a non-profit that puts on literary, artistic, poetry, and other events that require projection, so a 20 or 25 foot distance in non-total-darkness should, ideally, also be feasible. That's for showing high quality video.
2.) The home office would put the screen about 9 feet away - well, bit more, since it'd be a bit higher than where I'm sitting. But a throw distance of 9 feet and a screen width of somewhere between 60 and 70 inches in width. Good zoom, the ability to adjust the lens horizontally and vertically is pretty important in this limited space; keystone correction would be good... don't know if that's all possible.