Here is how my guild normally do it, we have two tanks standing about 35 yards away from each other, both with the wall at their backs and bosses slightly in front on them, and then we have the rDPS on left side and mDPS on right. Healers are standing in middles so they are in range of both tanks and all DPS (in range of everyone to put it simple), just before they jump right group make sure to back away a bit to avoid fearfull (if their target is about to jump the just need to hug the wall to the right).
When Toth leaps, the tank on the right without any boss quickly needs to take Zorn, however the tank that has both bosses close does nothing and will thus have no boss on him during this time. Toth will still have aggro on the "right" tank even thought he leapt to the "left" tank, so he will start walking back, and as soon as he is going to hit the "right" tank, the "left" tank taunts him and he will walk back again. This way you will avoid a lot of damage in the beginning of the jump and your healers are able to compensate with healing to get everyone up, also important is for healers to keep both tanks at 90%+ just before the leap to avoid deaths.
By doing the tank swaps this way you will also be able to let a few seconds go, meaning that the fearfull debuff (if DPS is that high) will never be a problem even thought one tank might have a little left when the leap comes.
Some pictures of positioning: