However the message text in the banner is left-justified, and this can't be changed in the Wizard. The left-justified text can look rather strange on a larger monitor, especially if the banner is set to run full width and the text itself is on the short side. It would be much better centered - but how?
Fortunately it is possible to center the text with one line of CSS, added via an internal stylesheet. The amended code block with added CSS (highlighted) looks like this:
I hope this is useful to someone out there!