Quick update - Sushi has now taken 4 weaned rats. It is to the point now where I can barely get the tongs inside the tank before he strikes. I have taken to putting some random glossy mailer down first do prevent substrate in the mouth. Solid feeding response, very pleased with how things are going. We are up to 286g, a 96g increase in the first two months here with me.
Sushi has also started mellowing out already. He was never fearful or nippy, but a little hesitant, quick head movements, etc. Now when I bring him out of the tank, its calm, slow movements, long tongue flicks, etc. More inclined to just hang out, tolerates me touching his head without flinching, just becoming way more laid back all around.