After urination, when should a man begin Wudu according to the text's rule of Istibra?

Istibra and Istinja: Rulings and Method

• When he is reasonably confident, according to his normal habit, that urine has stopped.
• Immediately, even while further drops are still expected.
• Only after a fixed 10-minute wait in every case.
• Only after performing Tayammum first.