Assuming your using ISB I have a "slave strafe key" assigned to shift + e for right and shift + q for left. On fights like tyrande I strafe left the first time and right the second. They dont stay exactly in sync but since you only really have to move 3 yards its so close you wont notice. The strafing back is the key. I have a ranged follow key assigned to shift + F that makes all ranged follow the window I am on.

On Bain I drive from one of my ranged the whole fight since the tank doesnt have to move unless his platform gets targeted. As soon as you see baine switch targets I hit shift + F and whoever gets knocked back is still in range to follow me and I never have to switch windows. If your current window gets targeted just move like you would single boxxing and keep spamming your dps key.