E8S Eden's Verse: Refulgence (Savage) Knockback Mirrors Uptime Strat (MM4)
Arm's length or surecast must take effect when the cast bar of the faster mirror is past the first "l" in "Hallowed" (example: https://i.imgur.com/VmUXfNU.png)
I was told that the tank for the team on the GREEN mirror's side needs to be in front of their party for BOTH knockbacks, a lot of guides do not mention this.
Tank must pop strong cooldowns, each knockback does about 170k to the closest player.