kevin, get video if you can - but if you're not getting enough height, make sure you're edging thru the top of the wake.
a tip i was given to work on backrolls (and that im using now to work on switch rolls): take a short cut, like 8-10ft out and edge harder. this makes you emphasis the load-and-release nature of the trick so you take it up, not out.
a lot of times folks think they have to cut in really fast. it's more about maintaining a progressive edge and exploding off the top of the wake. and yes, if you're not holding your edge, you're throwing it too early. you may also want to shorten the rope so you're not worried about clearing the wake.
as said, your handle position looks good and you've got both hands on the handle. i'd say shorten up your cut and concentrate on holding your edge. you'll come right around and move onto the "how the heck do i land this thing??" stage.