I was there today. Yes, MS's voice was nervous, shaky and quiet most of the time. Occasionally he'd pull himself together to answer a question, but it was visible it was wearing on him. It was my experience there was nothing I caught that made me think he was being insincere. Facial expressions and posture, seemed regretful. A far cry from when CN was on the stand. I get he would have been coached and advised on how to present himself and how much or how little to say. That said, I'm only sharing what I saw... and from that, feeling like he is telling the truth. Is he guilty of his roll leading up to and following the shooting; absolutely. Still fills me with disgust, especially seeing the pain and hurt of the Bosma family today.
Let's not forget he considered himself an actor before this, remember his gore filled rap video? 3 years is a lot longer to rehearse a part than most actors get.