I'm not sure as to how the "classic" piece values were found (probably just estimates of what exchanges worked and which didn't).
I think this might be helpful to you: http://home.comcast.net/~danheisman/Articles/evaluation_of_material_imbalance.htm
Everybody knows that the values of chess pieces are 1-3-3-5-9
the dynamic value of the king should be about 4
My question is: how these values were discovered? Just empirically?
If I design a fairy chess piece , given its properties can I estimate its relative value?