What is the test for finding an aider and abettor guilty of the felony murder special circumstance?

As stated by the state appellate court, in order to prove an aider and abettor guilty of the felony murder special circumstance, "the prosecution must show that the aider and abettor had intent to kill or acted with reckless indifference to human life while acting as a major participant in the underlying felony." Cal. Penal Code 190.2(c), (d) (emphasis added). To be a major participant, the aider and abettor must be a noticeable or conspicuous member, one of the larger or more important members of a kind or group. People v. Proby, 60 Cal.App.4th 922, 931 (1998). To harbor "reckless indifference to human life," the prosecution must show that the defendant has a "subjective awareness of the grave risk to human life created by his or her participation in the underlying felony." Id. at 928.