Prediction on how fast MNSSHP will sell out?

Just found out I have a conference in Orlando toward the end of October (yay!). I’m thinking I’ll try to get to the Halloween party but I’m not sure which dates I’ll be at the parks so I’m not ready to buy. Any idea how far in advance the parties usually sell out? My possible dates as of now are Oct 25, 26, or 28, so close to Halloween but not on it… Thoughts? Thanks!