I love the way the "Drop Shadow" preset leaves a transparent area on the
right and bottom of my clipping. But, each time I manually add some
space on the other two sides. (see video) Is there a way I can add this
to my default preset? https://www.screencast.com/t/mD1s8h6GE
One thought that comes to mind is that you could configure a preset that adds a white border to your image. Unfortunately, there is no way I'm aware of to configure the border itself to be transparent. But if you initially omitted the drop shadow, it would maybe be easier to add just the border. Then in the editor, just flood fill the white border with transparency. Then apply the drop shadow.
This is likely more steps than you were hoping to achieve, but maybe it helps.