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.
That's the way I play it. Eternal Decks have a 75 card minimum, but you can go up to 150 as long as 1/3 of the deck is power cards. I usually put a few more powers in than 25 and then add a few cards here and there to suit my taste. You could probably cut Champion of Wisdom and a copy or two of Bellowing Thunderfoot if you wanted. The market is up in the air other than Passage of Eons. I've only ever used Frenzied Omnivore other than that.