I am suggesting to use the TextAlignment="Justify" property(and the equivalent in HTML/CSS) default in the "Split" and "Grid" templates. The default (aligned "left") does not look good for long texts because it produces hanging paragraphs.
Justified text might look better if you're just looking at the shape of the grey space, but it's much harder to read. In the first place your eye uses the ragged edge to help it track when you're moving from one line to the next, and in the second
place you're much more likely to get vertical rivers where spaces in subsequent lines of text line up (since you have to have more space between words to make the edges justify).
I would refer you to Jan White's Editing by Design, the classic text for book and magazine design. His recommendation is that text should be set ragged-right if there are more than two columns or if the columns are more than 8 picas wide. Just because
most of what gets printed is quickly-produced dreck, it doesn't follow that dreck is best practice.