I can tell you one thing thou:
With ILSAC GF2 and onwards, over 90+% of commonly attainable, off da shelf motor oils are blends of Gp 2, 3 and perhaps more and with additives to meet auto manufacturer's and standards specifications. In other words: one cannot simply rely on using 1 group of base oil in order to achieve/obtain the desired results that will meet all the requirements out there.
So, bottomline is: why fuss over the type of oil? Afterall: most motor oils nowadays are at least type 2, with other gps of base oil added into the concoctions.
Q.