15+10 will give you enough time for instructional thinking during a game. I'm more interested in the middle game because I've learned from Stockfish that in some positions there may be two or three reasonable moves to go forward and, other positions, only one right move exists. Is it possible to see that during game play, or is that something only Stockfish can do due to its superior calculation? Magnus Carlsen says he can usually sense the best move even if he doesn't calculate it.
Through pattern recognition, you can develop an intuition from experience and so yes, there's many positions I just know the best move without calculating. Then small calculations follow more just to confirm the idea before playing it. It is certainly possible; engines aren't the only ones who can list multiple good moves. In fact, most high rated players will often mentioned two options they are considering... and these options are frequently the Stockfish 1st and 2nd "best" moves.
Btw, this happens at all stages of the game; it's just probably more common in the middlegame stage.
B) Rapid because it's the perfect length for a YouTube video.
A-D) All levels, marked in thumbnail.
Subbed!