I just saw this, thanks!
The amount of raw (solid) VII (VM) polymers used in oils are only about 1 - 2% for all VII types except the polymethacrylate (PMA) VII, which is 5 - 6%.
The rest of the VII sold commercially is a solvent (such as Group I base oil) used to dissolve the solid VII polymers so that it can be readily dissolved in the finished oil. In theory you can also dissolve the solid polymer in the finished oil but in practice that could give the blenders a huge headache and it's much easier to buy already-oil-dissolved polymers instead.
Yes, as your plot indicates, the relation between the VII content and viscosity is fairly linear, which is what I assume in my calculations.
The recent pair of papers by Hugh Spikes et al. discussed in this thread studies VIIs in full glory, with the Part II focused on fuel economy:https://www.bobistheoilguy.com/foru...y-hthsv-friction-and-wear-state-of-the-a