From memory, in that battle, you can effectively block both stacks of elves for the first couple of turns, keeping all enemy troops in place. And during that time, the wizards destroy the gold and pegasus units. But I don't remember the battle very well, so I might be wrong.

The sniper bow provides significant additional damage to archers when the hero has ranged attack as a secondary skill. Considering that we have Orrin and Frenzy, those 130 or so gold dragons from 600 wizards should theoretically be defeated in two shots ;)