Tier 1
Easily ToF, even without adds. So much synergy with StM! Adds just makes it even stronger.
Tier 4
Again, RoS is the best choice since you want those SW
when you pop StM.
Tier 5
AS unless you have really low crit (<20%) in which case you go San, SI if you have the legendary belt.
Tier 6
The difference between mindbender and PI isn't huge, but PI is better at keeping you in void form at higher StM stacks which is where you'll do most of your damage, so that's my recommendation.
Tier 7
Yeah, StM, no other choice