Re. D2XXL: I do not recommend using it for multiplayer. Even on my modern system the latest version is still unstable and crashes at least once per (single player) playthrough. Also, mixing source ports (some players in a game using D2XXL and others using Rebirth) in a single game is a very bad idea and can lead to a lot of weirdness in terms of game balance, missile behavior etc. The two developers are not collaborating with each other if memory serves (in fact I remember the two of them getting into massive flame wars). If Gold Leader mandates DXX-Rebirth, stick with that.
Given how quiet the Descent community is these days, it's easiest to just throw the levels you'll be using for a game revival event / tournament into a public Dropbox folder and share them that way before the event.