This was a forum post some years ago that I found very helpful when doing my own valuations:
It’s from January 2017 so it’s possible that things have changed a bit since SP are throwing fewer innings. But Justin went through and came up with how many players at each position are drafted in a typical Ottonue auction.
When you value players, you do so by setting a replacement level for each position (or collection of positions). This post gives some insight into how to do that.