Passive assistance on double reverse four-bars

What are the most effective methods of adding passive assistance to a double reverse four bar?
By this, I mean, Where are the most effect places to mount your rubber bands or elastic tubing in order to get the most benefit/passive assistance?

Either elastic tubing or rubber bands are fine, as we have both.

This was my best guess:

Thanks.

Rubberbands are very helpful for passive assistance.

Check out some of the RD4B robots in these videos:

https://www.youtube.com/watch?v=TVzuXcMy3bU