1) You don't need DIN 12. Your setting should sit mid-range on the binding's spring. If you skied a 4-12 your weight etc would not even get halfway up the scale. so, get a lower model. the binding's elasticity works best when the spring's pretty loaded.
2) the Axial turntable heel is the best heel on the market. they're the reason Look/Rossi bindings are so friggin' popular.
3) I'm 5'10", 160 lbs, level 8. I've skied the Axial 120 and Axial 110. They perform equally well for me. I ski at DIN 8.
4) so, I'd say get the 110 or 100 Axial.