I finally have it eating prawn and silversides! I got it eating nightcrawlers after it started accepting black worms more readily. After feeding the larger worms for a week, I began to cut MP into long strips and drop it in with the worms - eventually I phased out the worms and was only putting in the MP. It now seems to be fully on the dead food program, though is still skittish about eating while I am in the room. I feed a fair amount of frozen food to that tank anyway, so it isn't an issue to just feed a bit more to make sure he gets some. Maybe once he's good and fattened up I will try to begin converting him over to massivore...
I'm thrilled to have him out of the weeds and putting on weight though!