Id suggest not looking at your skis when you go to grab. Can stop your rotation and mess up where you are in the air. Like everyone has said just do them with straight airs to get that hand placement locked down. It might help to get your legs to do the motion and quickly grab and let go of your skis to get the feeling while spinning. After that feels good you can progressively hold it out longer and longer. Its what I do to learn new grabs and it works for me. I find anything over 3 forwards and switch is a lot easier to do with grabs. Just my 2 cents.