Help needed to choose the correct spiral springs

A quick learner from California says:
I could use your help in determining the correct parts to buy and I've attached three photos that I hope are helpful.

I have a 45" wide double glazed non-removable aluminum double hung window. The half that slides up and down/ opens is 23" high (x 45" wide) and the spiral spring clips at the bottom have failed. I can remove the springs by unscrewing the top retaining screw. All the windows in the house seem to be the same construction/brand, probably installed in the 1990s and some are imprinted with the word "Imperial" on the pivoting black aluminum sash lock release.

The diameter of the spiral springs looks to be slightly less than 3/8 inches (approximately 11/32").

The length of the spring casing is 23" and the tip color appears to be green (see attached photos).

The bottom shoe at the end look like the Balance Shoe 15-142 shown on your website and the shoe is 1/4" inch wide and the entire length of the shoe piece is 1 inch (see attached photos)..

I used your online spring selector and the closest match I could find seems to be the S306-23 23" Series 306 Spiral Balance. According to your website the S306 comes with an attached 15-066 bottom shoe.

Would the S306 springs with the attached 15-066 shoe work for my application or do you have a different spring/shoe combination that I should use?

Also, for tensioning the springs which tool would you recommend: the 75-004 or 75-005 charging tool?

Thank you for your help. Stay safe.

Warm regards,

Andrew
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Tom from SWISCO responded:

Hello, Andrew. I'm afraid the Series 306 will not work for you. The hook is not oriented properly to install on the bottom of your window. We did carry your clip at one time but the bad news is that we are no longer able to supply it. We only recently discontinued it. There is no confirmed substitute at the moment, either; due to the public health crisis, we have not had the opportunity to experiment with different options.

However one possible substitute could be the Series 400 along with a new 17-031 bracket, which would cradle the sash from underneath. It would require drilling a new hole and using a #8 screw. I cannot guarantee that it will work well, or if it's even possible, but we don't have anything else to suggest at this time. I apologize for the inconvenience.

A quick learner from California says:
Thank you for your suggestions. The tip color on my original spiral springs is green. Should I buy the blue or the red tip for the 23" series 400 springs? (see my original photos in previous post.)
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Tom from SWISCO responded:

In my experience, the modern Blue Tip should replace the old Green Tip, though they're not exactly the same. There is some spillover that the Blue Tip doesn't cover.

For reference, two 23" balances with a Blue Tip can carry 12 through 22 pounds. You an weigh your sash on a scale to see if it falls in that range.

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