jgnat: According to the WTS there is a separation between Jesus enthronement in 1914 and his "standing up" to judge (Dan. 12). I believe it was in the 1990s that it was "discerned" that he will stand up to judge (i.e., separate the sheep from the goats) during the Great Tribulation.
Starting with his enthronement in 1914, Jesus began cleansing the heavens, culminating in his casting out Satan to the vicinity of the earth by 1918.
Jesus will appear like a flash of lightening at Armageddon, which is projected to occur sometime after the Great Tribulation.
I hope that helps. (It's a strange occupation: trying to make sense out of an erroneous interpretation of a confounding book.)