Replacement channel balance

first 5 of ten pics of channel balances (can't find weight) 1st pic shows stamp on two of the three removed balances ... windows are double pane vinyl about 2'10" x 3'10" I am looking to replace the balances in 6 windows (all identical) the metal part measures 32" in length

here the second part - i rotated the end caps to all four sides hence the glut of pics