Need counter balance assy. for Regency windows

I need two (right and left) counter balance assemblies. Only one is broken but I'll replace both. The length is 23 inches total including plastic ends, The channel is 1/2" wide and 5/8" deep. The windows are about 20 years old.

I searched your site on 2130 and found your S385-22. They appear to be very similar except my bottom plastic piece is only 1-1/16" and doesn't have ears on the sides. I suspect that isn't an issue but you're the experts. I also have no clue as to the spring weight.