if this is a company build out like he says it is OEM has nothing to do with it. They'll have corporate level (size dependant) licensing for their software. Its not like they have a dell disk that is being used and it has to be that size because its what came in it.
giving users 2tb is asking for trouble. /users can't be bothered to back up their data in case of a crash thats the potential for alot of missing stuff wiht the possibility of impacting day to day functionality. If you limit them on storage capability and force them to use a file server that is backed up regularly that limits the chance of data loss. But I'll go back to my hole now. I dont really know what I'm talking about.