That's good I just hope it works for me, since the offset is throwing me off a little, if i tilt the projector upwards to lessen the offset will it distort the image too much? The other projectors I use they have a lens shift so in a short throw I'm not sure how I should go.
Your definitely going to notice that much alignment error. Add the 9.5" offset to the distance between the center of the lens and the ceiling and the result is the distance from the ceiling to the top edge of the screen. I'm guessing that mount will put the center of the lens approx 7" below the ceiling. So your screen will be approx. 16.5" below the ceiling.
You could build your own flush mount or partially recess you projector into the ceiling. This will get you close enough to avoid using keystone adjustments.
My projector is mounted 8" from the ceiling (to the top of the projector) and the image starts about 11 inches from the ceiling. I have it tilted slightly upward to get under a beam. I'm using the keystone correction, but I'm not noticing any difference in picture quality. You can use the mount as a flush mount as well if you remove one of the extensions. It is pretty versatile especially if you aren't sure what you are doing.
My ceiling is 7.9' so I was thinking wall mount (picture would be too big for room) or these two ceiling mounts.. If I did a wall mount my room from the other wall is 9 ft so that would make the image 84" tall and 172" diagonal, also if I wall mounted it a projector in it's upright position shoots upwards so that means I would need to lower the height on the wall which means sitting in bed would be an issue taking in account of the ceiling height.
but I was looking at these 3 mount types
it would be 1000 times better if I had the projector here now to see in person what my limits are but right now just going by what the data is on projector central, It wont be until after christmas I can get the projector now.