I was thinking. Why not have a thread where players who have not been able to get into a quest because they fill up too fast, or they don't have the time to constantly check for them, can place their characters name, class, level range etc and when a new plot comes up, the DM running it can check the list and place the characters name as a potential for involvement.
You can then add that if the player isn't able to or doesn't contact the DM running the plot before a certain time, they are removed and it can be filled normally.
Just an idea.
Because I have enough going on without doing extra paperwork when I plan my quests out.
That puts a lot of extra layers into the already troublesome task of scheduling, trying to get in touch with players who may or may not even still be active on such a list, waiting however many days to try to get in touch with them only to find out they're not available anyway, etc. If you want to get involved in more quests, Blackheart's thread
here is a great bit of advice.