I would appreciate some help with regards the correct height of my projector to the screen. Being a complete novice and now in the middle of decorating, I want to get it right so I can finish my decorating (and conceal most of the cables). I am mounting the pj on a ceiling mount, and the lens will be about 7'9" high. The bottom of the 6' wide screen will be about 30" from the floor, so my question is, will this be okay without getting any keystone effect (from what I have read on this forum it is advisable not to use the keystone adjustment). Having done the calculations for my benq 5120 (using the USA site), I am positioning the pj 3.24m from the screen, to obtain a screen width of 170cm, a height of 96cm & a diag size of 195cm. From what I have described, will I have any keystone effect and do my calculations sound right (eye to screen distance will be about 10')? Any comments will be appreciated, as I really must get this resolved so I can finish the decorating (and hopefully enjoy my pj).