Rosie, you should find the thread where I asked for constructive criticism on flips. Lots of good info in there. I started out with the same form as you, fully extended, back arched. After getting the good advice I did from Jace and a few others I started tucking during rotation and it sped up my rotation a lot. It really makes a difference, try staying tucked and whip your head back as hard as you can and you'll get them. You have enough height. If you're having trouble with getting more distance than height than you are going into your wake too fast, try to slow right down. Make your set up wake, turn around immediately, don't ride out too far before you turn around. If you turn back to your wake right away, you can basically stop, look to time the wake when it converges and ride up it so you get more height.
Rosie, you should find the thread where I asked for constructive criticism on flips. Lots of good info in there. I started out with the same form as you, fully extended, back arched. After getting the good advice I did from Jace and a few others I started tucking during rotation and it sped up my rotation a lot. It really makes a difference, try staying tucked and whip your head back as hard as you can and you'll get them. You have enough height. If you're having trouble with getting more distance than height than you are going into your wake too fast, try to slow right down. Make your set up wake, turn around immediately, don't ride out too far before you turn around. If you turn back to your wake right away, you can basically stop, look to time the wake when it converges and ride up it so you get more height.