Ok, I was able to install it and run it with the Ultegra 6700 - 12/30t.
I inverted the B screw and extended it as much as possible but noticed the RD cage cog (the closest one to the cassette) is very close to the 30t when chain is cycling through.
Also, another thing I forgot to mention is the crank I have is the Dura Ace FC-7950 compact crank. And also noticed the chain rubbing against the 50T in front. see photo
please help.. thanks.