Hmm.. less than ideal, especially since the padding at the top of the chart seems to vary considerably depending on the data, and our data varies considerably in scale. Sometimes there is plenty of room, sometimes it's right on the line. I'll need to add code to sum up all the elements in each bar and find the highest value and then guess at how much space to add...
Anyway, less than ideal, but it seems like this will probably work for now so thank you for the suggestion.
-Ed