I'm not really sure at this point if you've done them or not so my advice is to make the off-axis rotation of your spin at about the same angle as the jump you're doing it off of. So if the jump you're going off of has quite a bit of lip, you're going to be more inverted than if you're trying it off a step-over jump.
In the air it's really important to have a good sense of where you are in the spin, and in relation to the landing. If you're going to be attempting a cork 7, I don't necessarily think you need to know how to cork 5 first, as they are really the same trick, but if you don't feel you have enough speed or a fast enough rotation, compensate for that and stop your spin sooner, as not to land sideways and fall. Another thing that helps me stay focused is to try and focus on the backs of your skis for the first 360 to help set your inversion, and for the second half you should see your tips to help you asses where you are in your spin. Obviously everyone has their own way of doing things, that is just mine. Good luck, post a video of your attempt and hopefully people will have more pointers for you from there, assuming you need them.