You will know when the process is complete when you see the shed skin, its gray. It might come out stretched like the snake, it might come out all rolled up. Mine always comes out in a mess. But you'll know it when you see it.

Your snake will clear up just before shedding, so the eyes will look clear again and the colours look fine, but it'll be another day or two after that before she actually does shed. It's good that you have bumped up the humidity, I highly doubt there will be a bad shed, but you'll be able to see stuck piece(s) of shed if theres a bad shed. Yes mine usually shed in their hides, rubbing it against the hide walls or on itself to get it off. I'd wait a few days after the clearing up stage begins before checking. Or if your snake is active again and not pulling skin off herself, then I'd check too.

You can offer after she's done with her shed, but I'd say wait just a couple more days since she's new and just shed. Both are pretty stressful.