Based on the info posted in that link, That screen looks accurate for an actual 100" viewing area, (87" wide x 49" high)
Have you ever checked out a HT setup in person to see what your viewing angle tolerance is?
Viewing a scope movie (2.39:1 aspect ratio) at 87" wide from a 122" seating distance would put you at 1.4 screen widths
Which is very close to perfect for many people ,...about 7th row in the diagram below.
I'm at about the 5th row , just under 1:17 screen widths, with my 120" screen that's actually about 102" wide viewing area (116" diagonal)
It's a little too much for some people, I have no issues with it at all, but I would never have known if I didn't test drive several setups first.

That's a killer package deal at Visual Apex! Jump on it before its gone.
Many people regret going too small with their first screen after a month or two, almost no one says "I went too big".
Remember a jump from 50-60 inch flat panel TV to 100" may seem like a HUGE step at first, but once your used to it, you may want 12" more.
The 106" screen would put you at happy medium 1.32, So if you think you can handle moving up 1 row it's cheaper to do it now.
Personally, knowing my tolerance level after 4+ years with my current setup, I'd totally max it out and
go with a 112" dia screen (1.257) and be right at the SMPTE reference mark with a 43.4º viewing angle.
But that's just me.
Oh, and dont worry about the brightness on the Calculator, it will be about half that (or less) in a calibrated movie/theater mode,
it's easier to dial down a bright image than it is to crank up a dim projector and still maintain image quality/contrast.
I always check out the Art's PJ reviews here when researching info ... http://www.projectorreviews.com/epson/home-cinema-8700ub/index.php
Edited by PioManiac - 1/8/13 at 7:01am