I also put some joints in his hands and fingers, as these will be important for 2 of the poses that I am considering.
During the rigging process, I discovered a problem with Cornelius' feet, in particular his inner toes, they were joined together by the vertices!
This meant that I had to delete the some of the faces in both of the offending toes and then create polgon faces and extruding them to make new toes from scratch. I had to make sure these toes were not close to one another.
I did the same in the gorilla's arms and hands.
I also discovered that when I turned Cornelius' head, the top half would move further than the bottom half, creating a distorted effect, meaning I had to increase the influence of the head and neck joints, and decrease the influence from the chest.
I then went through the back joints and increased or decreased the influence to make sure his bending down is smooth.
The next stage is to set some driver keys for his face and possibly his hands.