How can one combine pondering the Quran with reciting it frequently, knowing that reading a Juz' (part) takes approximately twenty minutes? And what is the best method for pondering?

Frequent recitation does not contradict tadabbur (contemplation/understanding), unless there is excessive speed. This is because tadabbur requires slow, deliberate recitation (tarsul) and comprehension of meanings. Many texts affirm this, such as Mujahid's interpretation of "and recite the Qur'an with a deliberate recitation" (73:4) as "recite it with deliberation." Also, there is Ibn Abbas's preference for reciting Surat Al-Baqarah with tadabbur over reciting the entire Qur'an quickly, and Ibn Mas'ud's saying: "Do not scatter it like dried dates, nor recite it rapidly like poetry. Pause at its wonders and move hearts with it." Furthermore, the ability to engage in tadabbur while reciting a juz' in twenty minutes varies from person to person, depending on their speed of comprehension and understanding.