I know nothing about pacing. I’m not even convinced that it’s a thing. If I’m reading a story and get bored, I don’t say the pacing is slow. I say it’s boring. That tells you more ways and more specific ways to fix it. If a story has two breathless action scenes in a row in a way that doesn’t work for me, like the opening to End of Ponies, I don’t say the pacing is too fast; I look for something that's missing.