I feel that the list would be a good idea to use. One problem though, is if there are no players from the list online, or that they're playing a game.
From what I understand, admins take priority when reffing. If you can find one of us before the match, ask us if we can ref in advance, not leave it to the last five minutes. That way, there is a higher chance of getting an admin to ref.
If no admin is available, look at the list and choose someone that fits the criteria of being online and not playing in the match. If they can't do it for whatever reason, repeat this process. I would start an hour before so there's no rush.
If no refs on the list are available, that is when you pick anyone else from the forum.
I hope this helps for now. Obviously we will try our best to get an organised timetable up for refs, hosts and streamers.