My wife and I do have an award ticket for Thailand in September... Might buy myself up to E+ then buy her up before the flight if I don't hit 2P by then.
I thought that if you bought the annual E+ access that you could bring one passenger with you in E+ so there's be no reason to buy her up before the flight. If that's the case (and I'm sure others can confirm), you might want to go ahead and buy E+ access now to ensure you won't be in E- for your upcoming flights.