ilicone hardness & skin/bone/tissue details.

Silicone hardness can be altered quite easily using substance called silicone deadener or silicone oil fluid. The 3rd iteration prototype will be softer in touch than the 2nd version, but I will still keep it fairly harder than the real tissue. The reason is simple - the softer the materials are, the easier they are to damage. Such a high level of physical realism is not crucial to achieve learning goals in this case and is way less important than the durability of the product.

The same thing could be said about the skin/bone/tissue details, the high level of realism is not that important to achieve learning goals. The difference here is that the details, apart from slightly longer development time, will not negatively impact the durability of the product, its cost and production process. Because of that the new version will have brand new looks.