What are the maths behind paying factions for relationship increase?

[asanbr]

I use caravans a lot and transport pods to send gifts to other factions, to make them friendly.
It used to be possible to send silver with the comms console too, but this seems no longer an option.

I haven't figured out the maths behind how much to pay for +1 relationship. Does anyone know?

I have noticed that a colonist with better social skill gets a better price in silver/relationship point increase, at least it used to be like that with the comms console.

Is there a fixed base price in silver/relationship point, which is modified by social skill, and that's all? Are there other factors that also matter, like if it's a gentle / rough tribe or outlanders? Does it matter if I'm a tribe and they are a tribe too, or if I'm an outlander (crashlanded start) and they are outlanders too?

I have the impression that storyteller difficulty matters too, which would make sense, but I'm not sure.

When sending a trade caravan with lots of goods, is it better to first sell the goods for silver and then pay silver as a gift, or is it better to give goods as a gift directly, to maximise the relationship gain? Or doesn't it matter?

In the current game, I have the impression that the current relationship matters too, with diminishing returns. When the other faction was around 0 or below, it cost around 40-50 silver per relationship point, but I currently have to pay more than 100 silver per point, when they are at about +60 (almost friendly).


Etc etc. I didn't find much info when searching, but I'm sure someone has figured this out and written it down somewhere.