From an answer on stackoverflow to the question of "How can I increase the node size on dragging...":
An alternative to really change the size (in document coordinates) is to implement an "ExternalObjectsDropped" DiagramEvent listener than runs through the e.subject, which will be a GoJS collection, to actually modify the size of each Node.
I do not want to use the approach of a smaller initial scale in the palette and a normal scale (1) in the diagram
Is there an example of how to have a smaller node size in the Palette, and then converting the node size to normal (1) when dropping the node from the Palette to the Diagram? I guess the real question is: how do you start off with a smaller node size for the graph objects in the Palette?