Alot of things you know doesn't work in real life, also doesn't work in dreams. I have never been able to push my finger through my palm. Breathing with nose plugged is a much safer RC as it's hard to fail that one.

You don't need to do a RC to get lucid, I almost never do them and then realise I'm dreaming. I am already lucid when I do them and they work more like a stabilization technique.

Somtimes I have 5 fingers in my dreams, sometimes more than 10 total.