All the things you listed are really close to basic physics where one would get into fulcrum points, apexes and then spans into anatomical structure. Then scientifically one could say this dog should bite harder than that dog based on head structure, jaw length, scissor-ed bite, jaw muscle, and maybe even neck muscle. And as soon as we are onto something the exact opposite dog we are looking for will bite shit in half. Like your post said, lots of other variables, from the science of genetics down to the simple assumption is he biting as hard as he can in a particular situation.

So I can only respond to the post, not necessarily answer any questions. I think we can find some tendencies, maybe a little easier within a family/strain, but I doubt we can really nail anything down.

Great post. I too would like to hear the thoughts of others. EWO