what do you mean you cant push your heel down to release? like stepping on one binding with the other boot? I punched in your stats on a din calculator, saying you were a type 3 skier and age 10-49 and it said you should actually be at a din 9 or 10. so Maybe your binding is just stuck, or you need to push harder
lets just say skiing has been around longer than jesus.
Sweet baby Jesus 169 is short for your height. DIN is hard to say, because all bindings act differently. There are basic guidelines, but then it is all personal preference/the risk you are willing to take. You are the only one who can decide what is right. If you are scared they are too tight, loosen them. If you start to pop out too much, (and are willing to risk being a little tighter) then tighten them a little.