Patience is key; do this project when you have ample time.
"...Use some compressed air to blow crud away from the plugs before getting started....
...A few other things that helped: using a one-inch extension in the socket before adding any other swivels, extensions, etc.; and wiping a touch of antisieze on the plug's porcelain section so that once you finally tighten it in there and go to pull the socket off, it doesn't get stuck leaving you with a bunch of extensions and no socket....
Amen on both of those points!!!
It took me about an hour and a half and I had a buddy helping me out.
Be careful when removing the plug wire too. i ripped the rubber coating on one of the wires when pulling them off with with needle nose pliers.