Use a short extension and a jack stand. Place the extension in the socket and place the jack stand right in front of and just below the extension to support it. You want the socket/extension to point straight out, use shims under the jack stand to get it as perfect as possible.
This will support the socket and keep it in line. Now you can put on your breaker bar and cheater bar and when you apply down force the stand will keep the socket from getting on an angle and slipping off.
I'm used to working by myself and improvising an extra set of hands as needed.