So we've got our first huge project in Revit going into the city today. Besides knocking off early for beers, what is the best practice for "Freezing" a set at the point it went into the city? Should we just burn a copy onto a CD and keep it somewhere safe? We plan to keep working on some of the finish stuff, but that will of course impact the drawing set, and we need to be able to keep a clean record. Any other recommendations?