SYMPTOM

How to maximize Pie chart layout.

SOLUTION

There are a number of features that can help improve this scenario.

Labels
When labels are length,  label smart wraping can make them smaller as in this example:
http://www.dotnetcharting.com/gallery/view.aspx?id=PieLabelSmartWraping

Pie Sizes
If the pies are in one chart area, the chart will ensure they all end up being the same size. However, to ensure the pies remain the same size across different chart areas despite the labels, a static size can be applied as in this sample:
http://www.dotnetcharting.com/gallery/view.aspx?id=PieCustomSize

Legend
The legend can also interfere with pie sizes. To minimize the impact of the legend try the following

Put the legend in the title
http://www.dotnetcharting.com/gallery/view.aspx?id=PyramidCentered

Float the legendBox:
http://www.dotnetcharting.com/gallery/view.aspx?id=SplineTension

Position the legend on top or bottom so it's laid out horizontally:
http://www.dotnetcharting.com/gallery/view.aspx?id=LegendHeaderStyling