Simonton Window parts
Hello!
We can help with this. Our 15-111 pivot shoe which uses the 1/2" Series 160 coil springs is my recommendation. For a new double spring support, see the 15-150D. As for the tilt latches, take a look at the 26-243 and 26-244. Review the specifications and see how they compare with yours.
Also, this came apart in pieces. Do you have any videos showing how the double spring support assembles?
I'm afraid I can't say if the unmarked spring is 6.5 pounds without a stamp. To be certain, you would need to divide the weight of the window sash by the total number of springs in the window. We don't have a video on this specific double coil support but take a look at the video below starting at the 2:54 mark. The featured pivot shoe and coil support are different but the principle is similar and should give you a better idea of the assembly.