The first question is: what is the correct license metric?

This is a decision of the manufacturer, not of us as License Managers.

The metric combination on the license sounds somehow exotic to me. Installations assigned to users will require an explicit assigment of licenses to each and every user.

So using Installations assigned to organization or user assigned to organisation will be easier to maintain.

In case "user" is the correct metric and <ou need to change the application's default metric, you will have to

• edit the application
• add users as second metric, selet "set as default metric"
• you will not be able to delete the metric "installations" as long as there exist licenses with that metric
• edit all licenses and change the metric to "user"
• edit the application again and remove the metric "installations"