Stability on RFC

[Pacifist46]

I have a few questions regarding the star ratings for each stability measure on RFC:
1) In the Expansion box, do you get more stars for expanding more, or what? Because I would have thought that you did, but mine just plummets to 1 star every time I try.
2) "Synergies" in civics - such as?
3) The Expansion Civic - surely if I have 4 vassals and the Vicelroyalty civic (one that gives 4 stab points for each vassal) I should be pretty stable?
4) Just any advice really to get my Empire to Solid or Very Solid. I've tried everything, and I love everything else in the scenario like the Independence and the congresses, but this just annoys me really.
Thanks in advance for any tips.

 

[the343danny]

Expansion is the size of the actual empire in the real world. I thought I wasnt expanding enough as china because my expansion was low, so I expanded more and more, and eventually, civil war broke out for me. So playing as the Inca, you'd probably get low stars for expanding out of your original strip of land, although for them, you'd probably need to do so to win.