What is the ruling on one who delays joining the first رکعه of Fajr prayer so that he may perform Qunut alone, given that he is Shafi'i and his Imam is Hanbali?

It is not appropriate to intentionally miss a rak'ah with the Imam, because accustoming oneself to delay in acts of worship may expose a person to the danger of Allah delaying him from opportunities for good, and thereby missing out on great virtues, among them: the virtue of the opening takbir with the Imam. And whoever prays for forty days, catching the first takbir, will be granted two immunities: immunity from Hellfire and immunity from hypocrisy. Likewise, he misses the reward of hastening to prayer. It is neither wise nor religiously permissible to forgo these virtues for the sake of Qunut.