Not sure if it helps much but I notice you are soldering the wiring to the top side of both boards. You should be pushing the wire through till the pvc sleeve makes contact with the board (flush) then solder it from the back side. This will make for a solid connection and help avoid cold solder joints as well as weak wire connections.
Alternatively, you can bring the wire through the back side and solder to the top of the board. Whatever is easiest to get the wire soldered flush to the board.