I have a bulk download utility that I wrote for doing what you are asking.
In short, the utility is run in a Windchill shell.
The admin (or whoever) inputs the EPMDoc type, folder path to download to, username, password
Then stand back and let it run. Download is quick per file but if downloading 50GB worth of files it will take a while.
The number of files it can do is probably more limited by diskspace than anything else.
I decided to including entering doc type argument in order to run in three shells at once in the event there is a massive amount of data to download. One downloads assemblies, one downloads drawings (and formats), one downloads components.
It also creates a log of cadname rename history in the event the cad file was renamed.
So, that would be my recommendation.