Are you using the correct plugs as spec'd in the owner's manual? If you run too cold a plug you'll get carbon crust on the plugs and everything else in the combustion chamber.
I attach a universal joint extension and a 1" extension to my sparkplug socket and it works great. Once you have the plug half-way out you can remove the ratchet and turn easily by hand. Left-side plugs are definitely easier from below.
The first time I did it without the U-joint and it took hours to do all 4 plugs.