Beacon of Corruption - Mechanics

I was hoping someone could give me some more insight into a few things related to the Necormancer node "Beacon of Corruption".

1) Does this proc when you oversummon or a minion expires (as opposed to actually being killed/dying) ?

2) Could this be a good node for a necro and what sorts of things would be good to use with it (gems,passives,items) other than minion hp?

3) If you had minion instability, which also scales with minion hp, and a minion got to 33% hp - would it proc both minion instability and beacon of corruption?

THANKS!

1) Proc's when resummoned. Not sure on expiring, but prolly not since it doesn't trigger other on death effects.

2) Beacon of Corruption is affected by so little. If you don't get a lot of Minion Hp it's not worth getting. IMO. (also it's currently bugged and doesn't gain bonuses from support gems and possibly passive tree bonuses)

3) Yes they stack. If a minion get's to 33% or lower hp it'll explode from minion instability and then trigger beacon of corruption. Try Coruscating Elixir and Umbilicus Immortalis for fun.

Ghazzy made pretty nice video explaining it, but below are the answers:
1. It procs if you over summon as demonstrated by ghazzy.
2. Not sure about dmg, you'll have to experiment with it. Try with montegruls for high HP zombies.
3. Yes.