The difference I made in the Shadows Alpha only visible after I've saved and loaded the subtitle with playback via video, and not at all in the SubEdit's Text box. ???
Also very confusing and cumbersome, that the font sizes of the ASS are hugely different for the same font type compared to PGS. For FHD videos I use 54 for PGS and that's equals to 16 for ASS (comparing them during video playback) and with that setting it's impossible to relevantly edit or fine-tune the ASS style as it appears so tiny in the text box:
So I can only see the changes I've made after loaded and played back via video.
I guess I will report these for the "maker" on Github...