To be honest, I hate artificial feeling "sign up" scenarios and randomization as much as first come first serve stuff. Unless by "sign ups" you just mean like...making a list of who's interested and making it work. Honestly, since the game isn't very large, I don't think it's a lot to ask just to have some amount of OOC discussion about these things. Like, even just making an OOC post that is like "Okay, here's a plot opportunity, who wants in and how can we make it work?" would go a long way.

We don't have nearly a huge enough player base to demand much more than that yet.