Tilt spiral balance question

Hello! Based on your measurements, it sounds like you have the S600-25 spiral balance. The black tip option is rated to hold 31 through 40 pounds, which is fairly heavy as far as tilt windows go. It's also well over your given sash weight of 19.8 pounds, so your assessment is accurate: the upward force provided by the balance is way too strong compared to the downward force provided by the weight of your sash.

I think the Red Tip would be better, which carries 7 through 29 pounds. That should be perfectly sufficient for the sash weight at hand. The Blue will also technically still work, but it's 20 cents more. Ultimately it's up to you.

That tilt latch, however, is beyond me. I've never seen a style like this before. It almost looks like a bolt you'd find on a storm window, but I've never seen such a thing used on this type of window before. It's very strange. Would you happen to know the manufacturer?

Sounds good! I think that's the best plan. As for why the installers put in Black tips, it was probably because that was the only balance they had lying around and they just wanted to get the job done. That happens way more often than you'd think.

Best of luck with the project and please let me know if you had any other questions, especially if you wanted to try hunting down those latches at any point in the future. I can't guarantee that we can get them but I'd be happy to try my best, if you wanted to pursue that course.