Tips
The 540 Kick can also help a lot for the double pump variation. You could think of it as a 540 with a bent kicking leg, into a hook kick.
Swing your arms wide before your takeoff and then bring them into your body for a fast spin.
If you are falling forwards or backwards when you land, you are most likely spinning off axis. Try to stay as vertical as possible. Practice the second step of the single pump tutorial.
Practice your tsunamis and your Cheat 720 double pump will improve at the same time.