window tilt latch and balance coupling needed

hi: i cannot find window tilt latch or balance coupling after looking at all the local HW stores. Mine is shorter than all the latches available. Can you help please. For the latch the end to end length is 2 5/8 . the length without the tip is 2 3/8 . It is 3/4 wide outter edge to edge, and 3/8 in deep outter edge to outter edge. as near as i can measure the cut out slot for the latch, it is 2 5/16 long, 5/16 wide, and 1/4 in deep. For the balance coupling, the channel is 3/4 in wide and 1/2 in deep. The window opening is 5 ft by 3 ft .
I enclosed a few photos. Thank you.