LDN - Luminis Developer Network

Currently, our layout definitions are simple in that we defined a layout in the dlm.xml so that it's targeting a single role.

For example:
student-lo
faculty-lo
employe-lo

We have defined a new scheme in our test environment where we now have the following layouts and a user can only match with one.
student-lo
faculty-lo
employe-lo
studentfaculty-lo
studentemployee-lo
facultyemployee-lo
studentfacultyemployee-lo

This is nice as we have much more control over the content delivered, but the one thing we're worried about in the potential for making mistakes when updates to a layout is necessary. For example, should an update be required for the student-lo, then this would also be required for all other layouts that include student. There are some other difficulties that we foresee arising as well.

Has anyone else gone this route and if so, how difficult is it to maintain. Or, is there any other approach to layouts that you've used that you've found to be reasonably manageable that you'd recommend?