The problem is using a socket ( been there done that, even had one stuck once).
Use the original tool kit plug spanner and bar, and as the manual says do it standing at the front of the car and leaning over the engine, well you might need to move to the side.
The plug spanner is thin walled and fits. Also using this rather than a socket reduces the risk of over tightening and stripping the thread.
I have a socket that has around an inch of the open end turned down to be quite thin. Getting a ratchet onto the socket for the rear plugs is a little tight, a small extension bar is too long and no bar puts the ratchet up against the rocker cover. The ideal would be a small extension bar cut down by an inch, hmmm, I think I'll do that.
Number 8 on a manual v8 can be a challenge. I have found the type below can make life easier. Undoing the first time may require additional torque applied, but the handle length means its difficult to over tighten after that. The universal in the linkage is a big help. My old plug socket came with a reduced wall thickness . Supatool 16mm T-Handle Spark Plug Socket