Florida Extruders, the manufacture, is out of business. I have several windows that the springs have broken. Balances measures from metal end-to-end 29" with a width of 9/16". Channel is stamped with 28F only. Other information from the label on the windows is: Car # 279-170 Model 1000 SH Rating: H-LC45 1349X1600" (53X63"). I need sets of channel replacements for 3 windows this size. Please advise if you have an acceptable replacements.