I stay on a low dose, then pop an extra pill if I feel itchy burning nipples.
On 500mg of Test I stay on 0.25mg Adex every other day. Some days I need an extra 0.25mg. Although everybody aromatizes at a different rate. So bloodwork a couple weeks into your cycle is smart.
The main difference between arimidex and aromasin is that arimidex disables the aromatase enzyme temporarily, while aromasin permanently eliminates it. Some do better with one or the other. Both seem to have negative affects on cholesterol.