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.
I originally played with a 4th return but I found that it tended to be a dead card a little too often for my liking so I went to the one obelisk. Obelisk is a very strong card but it is a very weak t4 play usually because you are basically passing the turn so against any decks that can have fast starts like TJP and AP mid it is very dangerous to run more than one.
I would say no dawnwalkers. They are very bad against most aggro and midrange decks right now and the control decks usually come somewhat prepared for them.