I know there are more than a few car guys & gear heads around here. I found this recently (you may already be aware):
https://540ratblog.wordpress.com/
I can not vouch for the accuracy of his results, but his methodology appears to be valid. I know many of you will continue to taste, feel and fart on your motor oil in attempt to lift a thousand veils of viscosity and the like, but some of us will might find his method/results helpful.