Window Spring balances

I've attached some pictures of my window balances. I know this may not be sufficient for you to identify the specific parts I will need, but before I take the step of actually removing the window and measuring the individual parts, I was hoping you could tell me if you can tell if your spiral balances are compatible with my windows at all. I hope these pictures are sufficient. The windows are large and heavy, the lower pane is about 52" wide and 44" tall, double-pane thermal glass, aluminum frame.

Thank you,
Milo

The balances are 5/8" diameter, about 44" long. The tube is metallic grey and there is no colored bushing anywhere on the tube, so there is no other color to report. I don't see anything stamped on the tube, but as I noted earlier, I haven't actually taken the window out yet.