PBN external links frequency

Let's say you have four sites in your PBN. After about ten articles, you publish a article with a link out to your money-site.
How long after should you link out to your money-site again? After 20 more articles, or a few months after? Or do you just stick with linking out that one time?

I would just link out once per PBN site to the money site or you could include 2 links per post to different pages of the money site?