On a rig like this, I don’t think mGear is going to give you any specific advantage over any basic ikSpline or Ribbon IK techniques. I would use Ribbon IK here because you can more easily control the twist.
I think the main thing will just be coming up with a good control hierarchy, and driving the bend in the body based on distance between the head and butt.
And depending on if you are going for realistic or cartoony, you could drive some slight subtle bulge effects down the body by sliding a lattice or softMod along the straight version of the body, pre skinCluster. I see some gentle pulsing effect in his head I think. But I’d exaggerate that if it was cartoony.
edit: here is a cartoony example I did from a Wait Loss Cinema4D tutorial. The only thing about this rig was that there was an XPresso tag to drive the bump based on the distance. Otherwise it is just a simple splineIK equivalent in C4D.