I have an enumerated column, Kobo Status. It has several values: Send to Device, Sideloaded, Fanfiction, and Kobo Store.
Instead of sending books directly to device, I add them to a custom
Reading List. The plugin changes the column to 'Send to Device.' This list is synced to the device upon connect.
After the book is on device (with Kobo sideloads, this requires disconnecting to let it import, then re-connecting to Calibre), I run a custom
Action Chain, "Add/Update Book on Device." (It uses the
experimental chain variations feature.)
This sets the column to the appropriate value, and also runs a couple of additional tasks (setting reader font, uploading the covers, etc):
In the end, this is what it looks like in my Calibre library.
I should note that the square brackets are for the purpose of sorting within a user category.