I did the first configuration in a similarly sized room with my short throw and it was a big mistake. Your picture will be bigger if mounted on a shelf and you can distract from the unit with decorative books/sculptures etc. mounting it from such a short distance from the ceiling will give you dimensions closer to what you’d get from a brand new similarly sized flatscreen tv. Which kills the point of a projector for me.

The aesthetics of a ceiling mount will always look better but it’s just not practical in small apartments. Be sure to use toggle switch anchors, and check with your apartment management or even your neighbor that there isn’t plumbing on the other side of that wall. Also are we sure that isn’t a vent?