Which Stamp Option to Order When the Sash Weighs Slightly over 23 lbs?

Hi,

For years, I've wondered whether I would ever be able to find replacement parts for my failing Viking window channel balances. I discovered your site, and have been very pleased with the results. Quick shipping of a quality product. The 29" 395s I ordered worked out perfectly, the window in question has never worked more smoothly. Thank you!

I also ordered a 35" 395 series for a different window, 1 of 6 that will get new balances. It is the correct part, based on size, shoe, and top. I ordered the 3420 stamp option because that is what is printed on the existing (broken) balance pair. When I installed the new balance pair, it seemed to require too much effort to open the window, and very little effort to close it. I weighed the window, and it weighs 23.4 lbs. None of these 6 windows has ever functioned well, so I don't know how they worked originally.

Question: I know the 3420 is wrong, but which stamp option is correct when the window is only slightly over 23 lbs? 3430 or 3440? I definitely don't want windows that drift up or are too hard to close.

Thank you.

Thanks, Ben for the recommendation.