Why don't you put your collection in a dropbox folder and then invite them to share that folder? They can then add the books to Calibre themselves on their own computers.
How big is your big? If the person uses your link to install Dropbox on their own computer with a new account, they will have 2.5 gb which is at least enough for around 2,500-3,000 epubs (without too many illustrations).
If you really, really want to use the server, this thread discusses issues/how to set it up:
https://www.mobileread.com/forums/sho...content+server