I am a firm believer in removing the rad that is in your way when you try to remove that front plug, then pretty much any extension and socket will fit in the space. If you have the maintenance manual you can follow the instruction in it to shift the rad back or remove it. It will take an extra hr. for first timers but you won't flatten a bunch of the rad fins:headbang:. You also get to verify a bunch of electrical connecters while your at it.:thumbup:
While your at it here is a couple of tips. Those deep tunnels that contain the spark plugs can also contain dirt. If you don't get it out before you remove the plug from it's threaded hole, you may allow dirt to fall into the cylinder:yikes:. Your bike has a drain hole for those deep tunnels and it probably needs to be opened up. Debris eventually plugs it and it won't drain very well if water gets by the cap seal on the plug wire. Once the drain is open (accessible from behind the lower plug, you remove the lower plug and you can see it, but you have to plug it's hole to prevent dirt from entering it too) you can force the dirt out of the deep tunnels with compressed air after removing the plug wire & cap seal from the plug.