Here is an example of how to change the scrollbar width through scripting.
This example uses the javax.swing and java.awt to access the prefferedsize() property of the scrollbar. From what I gather, accessing the .width property for the JScrollBar directy is undesirable as it would bypass the LayoutManager inside Java (also, I couldn’t get it to work - says .width is not a valid property). So instead I set the preferredsize() property. This allows the layout manager to change the width property and appropriately handle resizing.
from javax.swing import JScrollBar
from java.awt import Dimension
D=Dimension(50,20)
event.source.parent.getComponent("Table").getVerticalScrollBar().setPreferredSize(D)