Your total testosterone dosage will depend almost entirely on the rest of your cycle. If you are running ONLY injectable testosterone as the sole compound of your cycle, then you're gonna need about 400-600mg per week for great gains. However, if you are STACKING testosterone with another injectable anabolic such as Equipoise, Primobolan, or even an oral such as Dianabol, Anadrol, or Winstrol, your dosage should remain around 200-400mg per week.
Testosterone is the father of all steroids, but in higher dosages side-effects do become apparent. Thus, it is always wisest to run a moderate dosage of testosterone in conjunction with one or more anabolic steroids. Testosterone should function as the BASE of your cycle, not necessarily the primary anabolic.