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Snap on 18 mm 3/8 drive deep socket will do the job
Best tool for the sparkplugs is the Honda one. If not in the toolbag under the seat, it is still available for a reasonable price at https://www.cmsnl.com/honda-cb550k3-four-germany_model14674/wrench-plug_89216323000/This is what has worked best for me. Before I mount a sparkplug, I screw the little ferrule on top, some non OEM plugcaps require, but... just a few turns. Now press the plug in the Honda tool, so the rubber, high inside that tool, will have a firm grip. The sparkplugs hexagon is now exactly where it should be and the whole combination is stiff and easy to work with, meaning the plug will not fall out. Screw the sparkplug down and tighten. Withdraw the plugtool and then simply remove that ferrule again. On removing the sparkplugs, do the opposite: withdraw the plugcap, carefully avoiding a too wild movement of your hand that may result in a compromised connection cap - wire or even wire - coil. Then screw the little ferrule on top of the plug - a few turns is enough - and firmly press the Honda tool on it. No risk of damaging the porcelain and guaranteed no more prematurely falling sideways of the #2 and #3 plug, which would result in a hassle to get them out.