I think you are not understanding my setup. Certainly, I'm not into jamming something where it doesn't belong.
I use a thin walled snap-on spark plug socket which has a built in swivel. I bought it on ebay new for about $25. see picture below:
I don't think the motor I have makes much difference??
Do you remember seeing a ball on a normal socket extension? Most are springloaded. Mine locks with a switch. You cannot remove the socket without sliding the spring-loaded switch. Take a look at the picture below and you'll see a black switch near one end of the exteions. That releases the ball.
Could you use a socket extension which locks onto the "lost" socket and from there pull the combined package out? If not, the valve cover removal advice seems good.
Good luck! I know with absolute certainty my setup works reliably.
Doug