get a lot of momentum and the first time when your hands touch try to push your self up high then guide your body by leaning in the air Hope this helped

Try to kick your legs up as high as possible without moving and then try to do a normal king with you legs higher that normal(don't hurt yourself with this high legged kong. You can really hurt yourself) and then try a double king and youll have the feeling of it already and you'll do it easier. Sorry if this is confusing.

When you go in for the first hand placement, don't worry as much about your height as you do focus on getting over it with speed for the second hand placement.