That prey is definitely too small. Pinky mice are usually far to small for any baby ball python. You want something that leaves a noticeable bump in your snake, not a huge bump, but enough to notice. The best way to gauge size is to get something that is as thick as the thickest part of your snake.
Your set up sounds good from what you say. If you are using a larger tank, one that can fit two hides, you need two identical hides. The hides should also be fairly snug, a bp should have to ball up and be a bit squished in their hides.
Also, about your fear of getting bit... If you have ever been bit by a kitten you have received a far worse bite than any BP will give youTheir bites are ridiculously minor.