I think this needs to be answered

[Niqote]

Seventy-five. Two on the cannons, one on the missile, two on the Vishap. Seventy more to throw themselves at the adds to keep them occupied since you didn't mention anything about having a tank or healer in the party.

At least with 70 SOMEONE will be capable of keeping the adds under the Bosses neck so the cannons can actually kill them