Custom PCB design 3V blinking LED project

I am looking for 2 custom PCB designed that will drive a flashing/blinking LED or series of LED's utilizing a sized CR927 button battery that is also activated by water. The form factor needs to be as small as possible. These units be potted with probes exiting the potting material the probes to be used as the water activating probes. Attached is a rough idea to what direction I am going in. I am looking for 2 PCB designs total one where the components are sided by side on the primary side, the other where the battery is on the secondary side and the LED's are on the primary [login to view URL] project goal is to have a small form factor units with a total component BOM cost under $1. LED I would like to use (not sourced from here but same LED) - [login to view URL] Thank you,