Which is better: the Abrahamic Salutation 100 times or the regular formula 300 times in the same amount of time? And is the Abrahamic Salutation exclusive to obligatory prayers only?

The Abrahamic Prayer is absolutely the best form of prayer upon the Prophet because he taught it to his Companions and commanded them with it. Taqi al-Din al-Subki believes that performing it is preferable in all circumstances. Al-Taj al-Subki narrated from his father that whoever prays with this form has prayed with certainty and will receive the reward mentioned in the hadiths. As for whoever uses a different wording, there is doubt, because the Prophet taught them how to pray upon him. It is also said that what is best is what brings more benefit to the heart.