Well, it is a risk either way, but if you want my risk assessment, I think that the highest teams usually will just switch places in their desperate attempts to gain higher rating.If some team gains rating, some other team will lose rating.

Personally if I was 21 of 31 I would just have gambeled that was good enough and sit on my rating, but as everyone else says, only you can decide

One way or another, it is an incredible result you have achived with your shamans.