Knowing that The Speaking Circle just wins games if you can protect it, time seems the most consistent at getting units down to protect it, and consistently get 6 power.
Against control decks, Ayur, Ageless Behemoth gets discarded to equalize and just wins afterwards.
Suggestions appreciated.
The ShiftstonedEternal Power Calculator is a deck-building tool that visualizes your odds of drawing enough Influence and Power based specifically on the cards found in your deck.