Hey and congrats on your first bp

At that size, he can eat food items around 15-25 grams, or as thick as his widest part of his body.
I would recommend rat pups instead of mice.

As for handling, most people say to not handle for the first 5 days to a week. Ive heard to start small and slowly increase the time, such as 10 mins then 15 and so on.

One sign of too much handling is refusal to eat, so as long as he eats, you should be fine. Also, most bps don't bite, so you're fine.