Thanks for posting! May I please see a photo of the top of your tilt latches? The side view helps however, I'll need to see the top angle to narrow down the replacements we can recommend to you.
In regard to your balance assembly, your balances appear to be the discontinued crossbow style balance. These have been converted to use our Series 795 Channel Balances. Since your balances measure 26.5", you'll likely need the S795-26.
To confirm that this is the balance you'll need, with certainty, be sure to confirm the diameter of the balance channel/tube (which should be 1/2"), as well as the width of the bottom T-shaped attachment, it will either be 1" or 1-1/4" across the bottom of the T shape.
If it is 1-1/4", the balances come assembled with the shoe you'll need. However, if it is 1", you'll need the 15-194 which is sold separately.
You will also need to obtain the exact weight of the window to select the correct stamp option.
Take a look at the video below for instructions on this balance conversion and the information you'll need to determine the correct balances. Let me know if you have any questions.