For forum folks who didn't see elsewhere, it's rather simple to play around with the highlight symbols that come with Accordance 10.3. I, for instance, was interested in a set less cartoonish with a consistent theme.
- Right-click or Control-click on the Accordance application icon in a Finder window.
- Select "Show Package Contents"
- Navigate to /Contents/Resources/ where you will see a "watermarks' folder with images 1 thru 130.
- Backup that folder elsewhere to be safe.
- Quit Accordance and have fun editing the images.
Note that any changes you make could always get replaced with new app updates.