You could try a different font type -
Go to Tools>Options>Theater View>fonts and try "Colonna MT", "Poor Richard", or Sitka Display". they look to have the smallest font size. I didn't try them all - but these did allow additional text to be seen over the default font used. It looks like only a "12 font" is offered even though there is a selection box for font size.
There is no way (I know of) to get three lines of text for the Cover Art in Theater View.
