Hello Chaley,
I use Calibre Companion for about three years now, mostly in "booklist" configuration, with the "comment" tag displayed in third line of additional informations.
Somme comments are much more longer than others and, therefore, much more higher than the cover display, so I wonder if it could be possible to get the option of truncating (in this view) this particular field to an optional length, just as it is done for the "Author" field.
An other way could be to be able to fix a "line max length" for each "column" of the book customization added information.
for your attention
Maxime