What is the test for reasonable diligence shown by a prosecutor in a search warrant application?

"Factors that a court should consider in determining whether reasonable diligence has been shown include the timeliness of the search, the importance of the proffered testimony, and whether leads of the witness's possible location were competently explored. [Citation.]" (People v. Thomas (2011) 51 Cal.4th 449, 500.) We are also mindful of the rule that the prosecutor need only demonstrate due diligence: that other theoretical inquiries were not made does not itself preclude the admission of prior testimony. (People v. Valencia (2008) 43 Cal.4th 268, 293.)