everyone is different so comparing to anyone else is not going to help you much... you generally start at 50 mg and assess from there... i have a method you can follow...
In short, the S4 molecule will bind to the receptor in the eye, which will cause a yellow tint to be seen in short amounts of time. If you stop taking the S4, the vision side effects will go away in a few days. It's not serious at all.
The 5 day on 2 day off usually eliminates the vision side effects for most people. If that doesn't help, only take the S4 on your hardest workout days 2-4 days per week.