Thanks for posting. Could you give me the width and depth of your pivot shoe? I would also like to see it removed from the window, if possible. As for the pivot bar, can I see a picture of one that is undamaged? I can't quite tell what you have by a broken piece. Let me know!
I think that will work but how do I know how many pounds?
If there is no stamp printed on the coil springs themselves, then you will have to remove the sash and weigh it on a scale. Any common bathroom scale should do.