When I was first learning them, I was hitting the lip basically on one ski, and jumping off that one ski to get the rotation. I dont recomend this style of spinning, because it is nearly impossible for me to get passed a 3 with it, however, it did help me get the grab and now I can do them spinning normally.\
So basically as you are hitting the lip, set the rotation, but also be bringing the grabbing ski up, I spin left, grab left. Youll be able to learn positioning and get the grab quick and hold it through.
I think someone had a sequence in a spyder ad that looks like they did it that way. I want to say maybe corey vanular? it was like a river gap and he was holding sticks instead of poles.