So, yes, tweeter diameter/size is a factor in dispersion but its dispersion needs to match with that of the associated drivers or timbre and that is influenced by its mounting and immediate environment. We see a number of speakers that remove the tweeter from the main box and place it in its...
It is a bit more complex than that. Measurement are not made just on axis but at all vertical and horizontal angles and the off-axis treble roll varies with frequency and angle somewhat differently in different speakers. Some speakers have wider dispersion at HF than others and the better ones...
For movies. streaming or movie theaters. Since I started with laser discs, I've found that I have no interest, generally, in watching movies more than once.
Added in edit: I do have about 200 BDs of opera and ballet but I consider them music with extra features.