Projector Offset question

Say I have a short throw and I want a 100" screen size or so.. on projector central it's showing me having a 9.5" offset for a 16:9 screen, OK as seeing I don't have the projector yet I was looking at this mount here http://www.amazon.com/Vantage-Point-CGUPM12-B-Universal-Projector/dp/B00067OR6K/ref=wl_it_dp_o_pC_nS_nC?ie=UTF8&colid=1NH884YY0W7K2&coliid=I3GH91HMVEMEEI


I ask all this because when I did a mock up on the wall I did not count in the offset but with the mount could you slightly tilt it up without distorting the image?

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.

The ceiling is concrete so that makes things harder.

Only other way I think it can be done is get a wall mount and mount the projector so it's not upside down.. however it would have to sit lower which would be another issue.

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.

Oh yeah I forgot about that one.