Me and zel did a test run on the day. I confirm:
1) Any member over 100 with 700-800k might can solo 3v1 and laugh. The mobs are pathetic weak.
2) We will NOT require 15 people if everyone solos.
3) We must drop one of the gates earlier to make the zergrush manageable. After that, defense isn't really needed... we just need to keep an eye on the big bastard time to time and that's it.