I would say that to learn a grab in your spin, first you need to get out of the mode of doing pencil 3's. To do this you need to just take anything you are comforatable doing, a grab, a spread eagle, an iron cross, anything you are super comforatable doing at any time, and try to incorporate it into your spin. You can try to do this at 180 while looking back at the jump or even earlier. Pete O. in an article wrote to look back at the kicker, since I already know how to grab spins I never tried that, but it could be good advice. Once you break away from your traditional pencil style doing any variation in your spin it should be easier to start grabbing more and more.