Wow, you have got very micro level knowledge about cricket and cricket ball. In INDIA, cricket is very famous and popular game and people are just crazy about it. Here in India cricket is next to religion. There is a strong emotional connect with the game. In INDIA, SG ball is used and it is little different from DUKE and KOOKABURRA.
I am aware of the SG ball, but never experienced how it plays. I suppose it is in between both balls and spinner friendly from quite early on in the game.