Busy week so far, so I haven’t had the time to clarify what I mean here.
When I say that you need to align on the acoustic axis, usually in-between the midrange (or woofer if 2-way design) and tweeter; I´m referring to the vertical plane. Unless the drivers are signal aligned in such a way that the directivity in the X-over range is “aimed” in another angle, you want to make sure to align the ear so it sits right in-between the mid/woofer and tweeter (or tilt the speaker so that the acoustic axis aims towards the ear. Again, I´m referring to the vertical alignment. In the horizontal plane (assuming correct speaker orientation = mid and tweeter vertically aligned), you can naturally “toe out” (well; not pointing away from the sweet spot but just not straight at it) your speakers and by how much depends on personal preference and the polar response of the drivers (especially the tweeter but also the midrange driver).
I personally try to angle the speakers so the apex of the close to equilateral (the head and the speakers form a perfect equilateral triangle) triangle ends up about 0,2 – 0,5 m behind the head. How much depends on the speaker and the size of the setup.