IMWS now can update collections as well. You can update all 'manual' collections: bookmarks, protection, flags, pins and dots.
A comprehensive example app is included in IMatch 2017 (click to zoom)
(https://www.photools.com/community/index.php?action=dlattach;topic=6420.0;attach=14661;image)
If you have specific requirements in this area, let me know. If I get no feedback from users who plan to write scripts, I implement only the interfaces I consider important.
better and better! :)