Best practice encoding time intervals

So I am excited about the ability to create Gantt charts, which fits to one of our company’s use cases. Yet, I find that the documentation is rather brief. Specifically, I am wondering what is the intended way to encode the “duration”-value. Currently, the index I am using to create the chart contains an @timestamp as starting point of the event and a duration field, which stores an integer and which represents the event duration in minutes.

What would be the best practice here? Is there a way to tell OS the unit or should I convert the minutes in microseconds or something?

In the documentation (Supported units or the OS-types listed for example in the SQL-Plugin-Documentation), while I understand how to query time intervals, I am a bit lost whether there is a possibility to directly create an field mapping for time intervals or not.