You can define role based layouts using Studio. In Studio WorkSpace, all the users are considered administrators, so you can use any user to define the layout. However the user must have assigned the roles for whom you define the layout.
When you define a layout using Studio WorkSpace, Studio stores the layout file in the BPM project. Later on in the development cycle you can publish this project in an Enterprise installation and import the defined layouts. You should use this option if you need to deploy your project in multiple locations, so that the layouts are included in your project and you do not have to define them for each location.
To define a layout from WorkSpace you need to log in as an administrator user. Your administrator user must have assigned the roles for whom you define the layout.