if you can do a normal tuck style tantrum, adding the grab shouldnt be to far away. the problem i see with this trick usually is throwing back your head/body instead of popping straight up off the wake.
so think of it like this, whenever you square off to the wake, dont lay out, pop straight up, suck your knees up and grab the board. sucking your knees up will initiate the flip, so once you grab you can look back.
theres also an indy tantrum how to in the wakeworld tricks section on the main page. check it out.