Just can't get these spiral balances to work

Hello! In answer to your first question, regarding whether a shorter balance can work for a window, the answer is "sort of." What you can do is drill a new mounting hole at the top to be a little lower than the original. Enough to make up the difference. The consequence of that is that your window wouldn't be able to open as far, but it would close despite having a shorter balance. It's not ideal, but without a reliable reference it's definitely a good fallback option. I've done it myself and I find it works fine, though it's a headache when you want to put in an air conditioner in the summer.

As for the pivot bar, you can't repair that. It would need to be replaced. It looks similar to our 26-203, 26-205, and 26-202, but you should try to use an undamaged version as a reference to verify whether any of these are a match.

Yes, if all the windows are identical then they should all use the same length. The only problem is, since all your windows use a different length, it's difficult to say what size to go with. 

If you are confident that the 33" and 30" long balances are operable then they would definitely be the pick.

I'm sorry for overlooking that part of your original post. The length of the pivot bar does matter, yes; if it's too long, it won't fit in the pivot shoe. If it's not long enough, it risks falling out. 

The bad news is that the three pivot bars I recommended above are the only three products we sell that have the same style. We don't sell them with alternate pin sizes. What you see above is all we have. These have a very unique design, since the pin comes out at an angle, so you won't be able to use any of our others as an alternative.

Yours probably isn't a factory defect, but just an alternative style that isn't made anymore. It definitely seems like someone repaired your windows in the past and used wrong hardware on half of them, so at this stage I really can't say for sure which is right and which is wrong.

I think I understand the issue here. The 5/8" dimension that you're referring to is not the length of the metal bar, it's the height of the plastic body. These bars are a standard size and shape, with the only differing aspect being the design of the body. 

All the same, it is odd that the one you bought from us is so long. If you have the long one in hand then I see no reason why you can't cut it down to size with a bench vice and hacksaw. 

I'll talk to our photo team and have them actually add the bar length to the 26-203 store page, since this has been a point of confusion. That should make sure this doesn't happen again.