Results vary among people, but, for migraines, I was taking 240 mg
Inderal LA (Propranolol slow release) every day, in divided doses, I was fine. One site I just viewed suggested dosing as 40mg twice a day of Standard Propranolol or 80 mg Slow Release once a day.
For the Standard Propranolol, they listed 640 mg as the maximum per day, in divided doses, so you're clearing that by a wide margin.