The leg rig is finally finished and I will now be moving onto the arm rig, it took quite some time to get used to using expressions and the node editor however the result is very rewarding. Once skinned I will make some playblasts of the rigs features, it has been very interesting to create so far!
The left side of the Node editor deals with making the leg stretchy correctly, it took a while to set up and to learn how each node worked. The right side deals with the flexiPlanes ability to twist successfully with the rig, it seems like the flexiPlane will be useful for keeping volume in the mesh as it deforms and creating some nice stretching/twisting.
the tutorials can be found here