How do i set a the Backward solver when I'm using the Full Body IK for the forward solver?

I’m trying to learn this Control Rig stuff and I would like if someone can help me figure this out. Or maybe someone has a link to a tutorial. I want to set both the forward and backward solver.

I’ve first tried with the example provided by unreal in the Content Example project, where each part of the body is set using various connected nodes. Got this working near perfect except that when adding an animation to preview the forward solver there are small movements both in the hand and in the legs. which is really annoying.

The backward solver works fine from what I’m seeing.

BUT

now I’m looking at the Full Body IK which appears to be better. But I’m not sure how to approach the backward solver with this node? It must be something obvious so if anyone knows would be great. Thank You