You can copy widgets across your existing overlays, similar to copying text across documents. Right-click your widget of choice and hit Copy:

You will want both overlays open in separate browser tabs.

Then, go into the second overlay's tab, right-click another widget then click Paste.

The right-click menu only shows if your pointer is actually aimed at an onscreen widget.

You can also use keyboard shortcuts for copying and pasting:
Click on a widget in your first overlay.
Press Ctrl+C.
Select your second overlay's tab.
Press Ctrl+V.