How best to resize XAML with dynamic text

Answer 1

I'm not sure if I understand your question completely.

Is it a case of your top parent stackpanel has been given a limit of x wide, but it's children are asking for a total width that is greater than this due to length of the labels?

In which case have a look at wrapping the labels in ViewBox controls (You'll find it in the Silverlight Toolbox library) This control will scale it's contents to take up the size available.