It depends on the purpose.
If you want to compensate the suppression of your natural testosterone, 100 mg/week should be entirely sufficient. However, it will further suppress endogenous testosterone, which will make the subsequent recovery more difficult.
If you want to make the cycle more effective, you can use more. But considering that people often use Anavar because of its low side effects, I don't think that running Anavar with testosterone would be much meaningful in such cases.