You will start getting high estrogen levels around week 3 when on a Test E cycle. With this, comes water bloat (the severity of it depends on the person), high blood pressure, and other estrogenic related side effects. Even if you feel fine on the outside, your body will be going through hell on the inside. Taking Aromasin (my favorite anti-e...very good on your lipids, doesn't effect the liver, and no estrogen rebound), will reduce these side effects and keep your body healthy. 12.5mg ED is a perfect dose.
Adding in the Clomid would be overkill, especially on a Test only cycle. Just the Nolva would be more than enough, especially since you are taking HCG throughout your cycle. Nolva and Clomid are pretty harsh on your body. I never understood who came up with the idea of combining both, but that is no longer done because it was proven, well...stupid. There are actually better things you can take for PCT along with the Nolva to really get your natty test going, such as Primordial Performances Testosterone Recovery Stack, or Needto's Unleashed. Nolva and Clomid were the only things around a long time ago. This is a new age and there are much more efficient products you can take such as these that work so much better.