Lovely, but doing it with only pressing one key (it doesn’t matter if you press while you’re drawing or if you press before and after you draw) makes things simpler.
What we have here is that you have to choose Ctrl+1 to go back to where you were. I hope that I am not the only one who forgets to release Ctrl when I am switching between (Ctrl+1, +2, +3, +4) and I happen to change my brush opacity or size. 🙂