In your advice your optimising for a single listening position.
I found, in my home, optimising for a coach with three listening positions, and a hard glass surface wall close to one speaker, that aiming the speakers away from the sidewalls and towards
the corner position at the
opposite end made for an ok result.
Theory being that this configuration would even out the drop in high frequency response at the corner listening positions, (closest speaker off-axis response matching farthest speaker on-axis response)
At the same time minimising first reflection from side walls.
In your advice your optimising for a single listening position.
I found, in my home, optimising for a coach with three listening positions, and a hard glass surface wall close to one speaker, that aiming the speakers away from the sidewalls and towards the corner position at the opposite end made for an ok result.
Theory being that this configuration would even out the drop in high frequency response at the corner listening positions, (closest speaker off-axis response matching farthest speaker on-axis response)
At the same time minimising first reflection from side walls.