11/16" open end will normally fit the wire end. If not, find a super cheap chinese open end and grind until it fits.
The plug itself is a regular 13/16". Just the plugs pointing to each other make it so a socket driver normally won't fit on top. A crow foot as suggested above will work. So will taking a chinese box end and bending it to clear. Think old time distributor wrench. With the other end sticking up, a long screw driver works great to give twisting leverage.
It seems there are at least 3 different length replacement plugs out there currently all with the same number. The shortest of these can be removed with a regular spark plug socket and driver. The other two sizes need to have creativity to get out one plug for every grouping of two. Then the other 3 can be pulled like normal.