Simonton coil balance spring

Hello,
I need to replace the coil springs for a simonton single hung tilt window manufactured in 1996.  the spring is 1/2 inch wide   The pivot lock shoe and cover are ok but the coil spring is broke.  The dimension on the window tag reads 23.624" x 27.313"
I cannot read the serial  number on the tag for this window, but the identical window in this set of two has the following serial number 6003089010002
I want to buy a set of springs (right/left) for this window but I don't have a part number or strength rating for the spring itself