What's up Chris,
when watchin your video, one thing foremost got my attention (besides the very nice location...) On your third try, when you're actually pulling the trick, you're putting your board more on edge on your approach, thus generating more speed. A good amount of speed is key to achieve this trick, along with waiting long enough for your pop. So cut out wide, dig your edge in deep and create a lot of speed early. Accelerate even more as you're approaching the wake. Don't rush the take off (this can result in great pain)! As you let go with your back hand, make your shoulders parallel to the wake/shore before you're leaving the wake. This is sooo important. Straighten your legs at the TOP of the wake. The wake will trip you up in the air and you will receive great pop. When you're on your way down, make sure, you won't land straight-legged, then your landing should be really smooth. Once you get consistant with big and clean Tantrums, try an Indy Tantrum.