InRoads IRD Files

IR XM & V8i

Just curious.  What is the best practice for project IRD roadway libraries?  Is it better to have a single project IRD with scads of corridors, or multiple IRD files that contain much fewer corridors?  Does anyone have any insight for which method works the best? 

We require a consolidated template ITL library at the end of the project, but don't know whether if that's the way to go for IRD libaries also.  TIA...