At 250 every 5 days, there is a good chance that you will not need an AI. Not a bad idea to have some on hand, either Adex or Asin. Your best bet would be to get bloodwork done 4-5 weeks in to check your levels. If your estro is high then add the AI at that point. You can add it before if you are getting puffy (and it's not diet related) or if your nipples are getting itchy and swollen. But 350mg of testosterone per week is a very low dose to run for 12 weeks. You will need to set up good pct and have it before you start. If you can get HCG that would be a great addition for the last month of the cycle, before pct starts.