When working with the Layout feature of the RadDiagram you need to keep in mind that the layout considers the way your shapes are connected. This means if you create a graph that is not symmetrical, the Layout algorithm will not create a symmetrical tree as well. This is why the most important step that you need to make is to create a symmetrical tree with your shapes before using the Layout algorithm.
I cannot see any obstacle in using the Layout at runtime with dynamically added shapes. At the time of performing the Layout you can traverse all the available shapes and find the roots of your structure. After that you will be able to create the necessary settings for the needed layout and use them right after.
Pavel R. Pavlov
Check out the Telerik Platform - the only platform that combines a rich set of UI tools with powerful cloud services to develop web, hybrid and native mobile apps.