Is it permissible for an inquirer who believes that the soundest approach is to rule according to the strongest opinion (al-rajih) to seek a fatwa from a mufti who issues rulings based on one of the four schools of thought? And is it obligatory for a student of Islamic law who studies a specific madhhab to search for the strongest opinion, or is it sufficient for him to act upon what he has learned from his madhhab?

The origin of the question lies in a misunderstanding that there is a ruling that is definitively preponderant in an absolute sense. Preponderance is a relative and additional matter that differs among scholars according to the evidence that appears to each of them. The adherents of the followed schools of thought establish rulings based on what they consider preponderant according to their own understanding. It is inconceivable that Muslim scholars would intentionally contradict what they believe to be correct. Therefore, if you understand that every school of thought is preponderant to those who adopt it, and that there is no absolutely preponderant opinion, then know that it is permissible for a layperson to seek a fatwa from someone they trust in their piety and knowledge from among the followers of any school of thought, and to act upon the fatwa given; because that opinion is preponderant to that particular mufti, and by doing so, their responsibility is discharged.