What would you do?

So I was just in this game. (Still am) Anyhow I was faced with a situation and thought long and hard about. Here is a screenshot.
I had 6 cards and 2 sets I cashed one set because I had to. It was worth 20. Now we were at the other set. Cash or hold? Kill Orange or Go for Gray? Why not Kill Teal? Cash both and kill gray? What would you do and why?
Gray had 18 armies
Teal had 27 armies
Orange had 28 armies
I had 6 cards and 2 sets I cashed one set because I had to. It was worth 20. Now we were at the other set. Cash or hold? Kill Orange or Go for Gray? Why not Kill Teal? Cash both and kill gray? What would you do and why?
Gray had 18 armies
Teal had 27 armies
Orange had 28 armies