Cause the thread was closed to soon by the mod heres my reply:
as the raids are limited to 25 men but u can party up to 40 people just invite 15 other locks ( many of the players have 2 accounts so this would not be so hard )
so you should get at least 15 people soulstoned ( obviously more than 15 as there are some lvl 70 warlocks who will be in group) which is imo enough cause a soulstoned tank is mostly useless when loosing all aggro
have fun with this and correct me if I am wrong
(grouping more players in a raid will not show a message that there are to many players in group to enter dungeon - testet in kara)