Also "Hang a big schedule where every helper can be listed for when, where and what needed in the staff room (not to forget helpers who kept be free for jump in here and there). Have a couple of reliable other "main helpers", who can be asked and consulted by any other, specially new to the subject helpers."
Definitly being done :) Everyone will be shown the staff room and there will be this list plus list of events timetable on whiteboard, also all the packs for the showings - copies of the movies/episodes and the rating which will be hung somewhere - will be placed in here. When a show is set that your over viewing you head in, grab the pack and set up the room :)
In the past some con's had had their staff manager do up a full schedule for each staffer telling them where they should be and what they should be doing etc at any given time, this means that you always know where someone is, that a job is covered and that someone wont be stuck with one of the crap jobs all weekend.
However it can be alot of work to draw up and enforce but its still worth considering