Killing Phinney

[Velerin]

On live the strategy I use to kill Phinney is just invis and swim down to his lair (the seahorses only rarely see invis and if they do you can still go down on the opposite side of the see invis one).
Just wait til Phinney paths to the other side and you can get down there easy. Set up and then get him when he paths back and the seahorses above don't aggro as long as you fight on the bottom of the lair.
Here is not quite so easy since the seahorses seem to always see invis so they would still need to be trained away. I want to try it sometime but thought I'd ask here first to avoid needing corpse summons. Does anyone fight him down there?
The standard pull horses away and pull Phinney up to the ledge works ok but its annoying when he stops to cast forever and then the horses aggro on the way back.