Your pin appears to be straight - maybe rounded on one end and flat on the other - trial and error will tell you which works best. I'm thinking your notchy thingy 'dome in' will work better - you will know when you try to release the tension by raising the presser foot. The machine will not sew if it is wrong. If nothing happens when you lower or raise the presser foot something is wrong. That center pin has to push against that notchy domed thing - if it doesn't reach nothing will happen if it is too short nothing will happen - they are precision built. I've never seen a tension that needed you to thread through the loop in the spring - I can't imagine why you would need to. Do what works.
Last edited by miriam; 06-09-2013 at 06:26 PM.