you just have to cram your hands back there and do it by feel , if it was easy everyone would do it , I've used an old motor cycle mirror many times to see what I can only reach with my hand .
For ease of removal, you will have to unbolt the rear transmission mount from under the car. Then unbolt the right engine mount. You then can use a strap wrench attached to the back of the upper intake using the radiator support to pull/rock the engine forward to access the plugs. Then undo the strap and tighten up the mounts again.
put it in neutral for that , that little bit of space will make it that much easier
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