I have seen and will try to implement the VLC help instructions for creating the black border and lowering the the
subtitle text to read more easily below the image.
www.vlchelp.com/how-to-change-subtitle-position-in-vlc/
A preset to do this at the subtitle page setup would be most helpful and less confusing since a permanent change for
a viewing seems to be the only option-- then resuming the normal screen image after viewing the content with subtitles.