1. You are the first to report problems with font size. I would appreciate if you provide the steps to reproduce the problem with font size.
2. The Telerik.Windows.Controls.Map.Location.GetCoordinates should work as expected. You just have to pass right screen coordinates there. It shouldn't be a position relative to the RadMap control, but position relative to the inner component. I would recommend that you use MapMouseClickEvent on RadMap control instead. It passes valid geographical coordinates as event parameters.
All the best,
the Telerik team