I'm not sure if we have the hardware you're looking for, but I can try my best to find something. Before I recommend anything, can you tell me the exact size of the bracket? You said that the one you have now is too long, but I need to know what exactly it is you're working with. I also want to know the exact width. Thank you!
I think I can help. The long bracket that you're showing on the right in this photo was an older type that Stanley, the manufacturer, discontinued. They have since replaced it with the 23-306. The shorter one on the left is the 23-302, but the 23-302 is not compatible with your track. This was designed to be used in a newer style track like the 23-509.
The older, longer bracket was purposely made to prevent doors from banging together when fully open. To my knowledge, they don't make a shorter kind.
Thanks for your patience during the holiday season. We have detailed dimensions of the 23-306 on its store page that you can review. I will also post them here for you to review.