an adjustable mont will allow you some leeway. ohterwise its critical to have the pj LENS placed in the middle if you dont want to use any digital keystone. another point is that there is no horizontal keystone correction with this pj and there is an offset to consider. yuo can use a piece of string to make sure that the corners of the projection area are equidistant from the lens. if you can allow some leeway on where you project on the wall( no black borders to aim for) then that will make it easier. heres a pic of my diy method. the top plate allows sideways movement.