#1. Use tactic 2 and block the spiders and liches with the remaining units at the beginning of the battle. If we guess the opponent's tactic, it's a clear advantage: their troops won't have time to attack, and we'll have more room to maneuver.
#2. Add Petrification and cast it on our own spiders before Sacrifice. As a result, all troops receive 0 incoming damage for 2 turns.
#3. For summoned elementals, use "wait," then set them to defense and cast Sacrifice on them. -50% incoming damage due to the "Spirit" trait and an additional -33% from Sacrifice itself. OMG, elementals!
In general, I'm amazed that this topic has been around for a week and has 200 views. Either I'm writing poorly, or this forum is really just for necromancers.