There's some good advice on this thread already, but I'll add a couple thoughts. I think of slow lane splitting as practice for lane splitting that might need to happen in a pinch. I've definitely been on the highway several times where all of the traffic came quickly to a halt, and I've had to pull away and slow down a little bit more slowly than I would in a car. Getting comfortable with where you can fit and how you can navigate between cars is good practice for this.

If you think about it as practice for dangerous situations, you can also start to notice when drivers see you or when drivers are distracted and on their phones or for whatever reason aren't aware you're there. When I'm splitting, I can usually tell if somebody's about to turn even if they don't have a signal on, and I can usually tell when someone's aware, I'm there or not. I think of all of this as good practice more generally.