with subtitles, I have several difficulties (720x400/480). My suggestion would be, 1st value a maximum resolution
of 704 to be used. use the automatic crop settings. This can be less than 400/480 in the 2nd value.
This works perfectly for me, all subtitles are automatically displayed correctly.
(without any lines in it, this works also with 3 lines subs very good)
btw: Hello Signals, hope you're right.