I've been slow to update but I'm pressing on. The last couple of nights I had been working to catch up and I often finished with a trip straight to bed. Among the blends I have created I have sets for the knuckles, the wrists, elbows, shoulders, neck, collar, hips, knees and the ankles.
The key issue I had been encountering was the rear had unexpectedly warped. But after a number of workarounds as at the stage I discovered the problem the arms and the neck were done but weren't causing the problem, so I wasn't too keen on rebuilding those. The workarounds seem okay, and some artefacts from the masking could be hidden by the textures to come. It did have the unexpected positive side effect of adding minor muscle twitches in the thigh when the lower legs are moving.
To stop the blended shapes form exploding horribly if moved too far, each of the joints attached to an interpolator have a movement limit based on the values for their end-poses. it doesn't stop all horrible breaking but ensures especially with an IK that if a section the limb moves beyond the interpolation marker it doesn't violently mangle or implode the geometry.
one of my mistakes in building the blends was I hastily disconnected all the controls. So I have to reestablish those. Fortunately the fins, perhaps the most time-consuming, only took an hour to rig. In rigging I also have an aim constraint attached to the eyes, which allows for more easy movement with the central control than the previous system of linking together the rotation attributes.
Most of the nodes have been reconnected. All that remains to link up are the fingers, toes, and the head tendrils, I've updated Mudbox so a normal map to give texture should be in the works tomorrow.