What level of prevalence or number of reports is required for testimony based on widespread knowledge (Istifadah)?

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The statement of Ahmad and Al-Khiraqi implies that testimony based on widespread knowledge requires that reports become numerous, heard from a large number of people sufficient to establish certainty (Yaqin). Al-Qadi in 'Al-Mujarrad' stated that hearing from two just individuals whose reports settle the heart is sufficient, as rights are established by the testimony of two. This aligns with the view of later Shafi'i scholars. The first view is consistent with the linguistic meaning of Istifadah, derived from the overflowing of water due to its abundance.