For your weight, ability, & boot sole, DIN 6 sounds light. If you're over age 50, the shop will take the DIN down a notch. Keep in mind, the shop should set the bindings via torque testing, not by what the numbers scale on the binding says. Could be the bindings torque test different from what they read. More to your question, though -- DIN charts put you more in the DIN 7.5-8 range w/out age adjustment (don't crank 'em down based on what I say, though). Regardless of your DIN, typically a DIN 12 binding has more going for it than just a stiffer spring, vs. DIN 10 or 11 bindings. DIN 12 bindings usually have a better build, stronger, more durable components, more elasticity, etc. That's why they cost more. Whether you're a DIN 6 or 8, you can fit into any of the DIN ranges you mention, but if I would buy a DIN 12 model for the better build.