To cure downswing black-out, visualize the path of the clubhead through and beyond impact per 8-0 #3.
Also per 5-0, Monitor all three elements of the club (1-L) by way of the hands-stop monitoring the clubface instead of your hands.
Lastly check your balance. When you loose your balance, no matter what you are working on, your central nervous system will over-ride it as a defense mechanism to protect you from getting hurt.