as you already noticed the deploy command expects have deployment unit as parameter directly. So what you might do is to create your own command (or extend the existing one) that will be capable to create deployment unit object from string if not yet available.
Please note that executor currently might not respect strictly time of execution.
Another approach could be to use process that:
- when started will set timer to a given time when it should be resumed
- user REST work item handler to request deploy of given artifact
That way you don't need to manually use jobs but simply start process instance giving the date and time when it should happen and the GAV of project to be deployed.
Maciej, thank you for suggestions!