The highest I ever went with testosterone was 1 gram per week. I really didn't see any additional benefits from 500mg/week but I got a lot more water retention and felt like a 'bloated water buffalo'.
In my opinion, the sweet spot for testosterone is 500mg/week. Anything more then that is going to really start aromatizing into estrogen (even with an AI). Instead of increasing your testosterone dosage past that, you would be much better off add in another compound.