The front page of HN will get you 4k-6k visitors

It definitely varies depending on the type of content and how long you are on the frontpage for. My two most recent posts on the frontpage https://news.ycombinator.com/item?id=33248488 https://news.ycombinator.com/item?id=32104669 got around 20-30k views. They both stayed on the front page for over 8 hours.

I expected more like 15-20k. That seems a bit low to me.

This seems light. I got 20k for my horse ranch from a comment[0]. I expect more if you have an actual link, no?

[0] https://news.ycombinator.com/item?id=34482433