Hello! We definitely carry these parts. See the 15-192 pivot shoe, 15-156 cover, 15-157 drum, and finally the Series 170 coil spring. The video below will also show you how all these parts work together.
Give us the exact weight of your window sash, and we can work out the spring weights you need.
I've never seen that pivot bar, unfortunately. I'm not sure if we can replace this, but give me a little time to look into it and I'll get back to you as soon as I have more information.
Concerning your springs, I'm not sure that I understand your question. You said that you need another spring that's anchored to the pivot shoe, but all springs are anchored to the pivot shoe. That's how they're designed to work. Are you saying that your shoe uses two springs on each side instead of just one? If so, you want to also use the Series 171, as indicated by the video I showed you in my first response.
Since your sash is around 24 pounds, you want to use two springs one each side of the window, anyway. I recommend using one S170-406 and one S171-406 on each side; that's 6 pounds per spring, which adds up to 24 pounds of support per window. I highly recommend rewatching the video I posted above to get an idea of how these parts interact with each other.
In the meantime, I will do my best to track down that pivot bar.
I believe you have the Certainteed new construction window that uses 26-353 pivot bar. I wouldn't worry about whether your window is double hung or not. The parts Tom recommended above will work for you.
