I have a broken window channel balancer from a Pella single hung window. From my research, it appears to be a Swisco 795 channel balancer. The channel length (channel only) is 26" long, and the lower pivot assembly is 1" wide. The top cord attachment is a hook rather than a screw attachment.
This is for a unit in my home, but I am glass/glazing project manager. I have more knowledge than your average person, but all of my experience is in commercial systems.
Please let me know what I need to order. Feel free to call