I would just feed one weanling, 10-15% of his body weight every week is fine at that size. Once he gets up to 500 grams a small rat weekly will work.
He is actually around 480, I just got a good recent weight on him. I'm going to go ahead and feed him a weanling and maybe an extra fuzzy if he wants it on a 5 day schedule, and I'll switch him to smalls at around 600-650. Thanks !