Have I stripped out my spiral balance?

Hello, My name is Greg. I purchased a couple 41" green tipped 3/8" spiral window balances from you about 2 years or so ago. I just now decided to change them on the window. I replaced the balance and the shoes. I got the window to hold it's position when it was raised all of the way. It would not hold itself up if only opened 6 or 8 inches.

I used the tool and attempted to tighten both sides up another 2 or 3 turns. This probably would have been about 30 or 35 turns total on each side. The balanced striped out. It unwound and would not stay if you turned it more than 6 or 8 turns.

I am assuming that they were wound to tight. My question is should I go up to the black tip or change to the other size spiral balance? I am not sure if there is enough room for the larger diameter balance. I am not sure of the weight of the window but it is about 42" X 45". Your advice would be appreciated.

It looks like it will be close but I think that the larger size will fit. Is the 2 options to either go to a stronger 3/8" or change to 5/8"? Is the green the strongest 3/8"? I also replaced ordered new shoes when I ordered the other balances. It was the Product Code: 15-121 that I used.

thanks....