Replacement Balances with Different Numbers

Hi! I recently bought a home, with some issues with the windows. The windows are newer double pane, however some of them are missing the balances that hold them up. I have 3 windows like this, and I found two remaining balances that were previously used. I will enclose a picture of the window, and the sticker with the brand/size info. The first pictures are of that window and balances that I found. How do I know that they are the right size? The balances have the numbers 18-4 on both.

The other issue i have is with a large window in the front of my house. It is a large window with two smaller windows on each side, that can open/close. The large center window cannot be open/closed. The smaller windows are incredibly hard to close, and I would like to know what replacement would work best. I will enclose a picture of the window tag and the balances. I have removed the balances, and found that each one (within a single window) is different. One has the number 25-4, and the other has 25-3. It seems the spring in the balance is very strong, and the window is quite small. DO you have any suggestions?

Thank you for your time and expertise!
Erik