It's the width profile that determines tiller shape, side profile will show any 'irregularities' on your particular stave.
You should be able to get a few more inches by working on the center section. Go slow and steady with lotsw of shooting inbetween wood removals. Last thing you want is it bending too much in the handle because you will get bad handshock but the flipside is you need to get that center sectuion bending more or else your outer limbs will start taking too much set.