[quote=@Sho Minazuki]
I feel like 20 is too many for an RP like this. Maybe for something with the military and team work touch to it, like RWBY or the RP is played where everyone is in the same group or faction, it works because everyone has to abide by a central system or allegiance. Around several players would be good for a Pokemon RP, so long as they're committed.
[/quote]

I agree here; in a sense have 4 groups of 5, 5 groups of 4, and so on.

For those who get left behind or drop, I would say keep moving forward with your group. If anything, they could split off or do their own thing. But if they come back, have a chance encounter with the group they were in or another where it fits. Regardless hopefully everyone doesn't jump around too much like last time, because that was sort of the straw that broke the camels back for me xP

This should be moderately challenging to pace.