Ian, I know what you mean about the "looking around" thing. The advice to "spot your landing" has never been much help to me. I'm spinning too fast to see anything. If I get a big floaty launch where I could spot my landing then it's so easy I could close my eyes. For me it's all a matter of feel.
As previously mentioned, you are coming off your edge way too soon. Here's a vid of me a few years ago. You'll see that my cut is not that far out and I flatten out right before I snap the board backwards off the wake.
http://john.panelmagic.com/w800kbps.mpg Another thing that will help you is too get more weight in the boat. While your wake is big enough, a bigger wake makes a good crutch for landing that first roll. Way back when I first learned, I tried about 200 backrolls behind my unweighted Nautique (doing what Andrew described) and was ready to get a lesson when some guys asked me if I wanted to try behind their heavily weighted 2001 (the pre 90's hull) Nautique. I landed 3 in a row. Got me about 700lbs and was go to go after that.