Any plug that fits an XX fits an XX.
I find it comical that so many different sources list so many different plugs, and even Honda changed specs.
But they never changed any part of the actual spark generating system.
The only purpose of iridium coating on either electrode is to reduce wear. They don't reduce fouling, and that's typically one of the two reasons 98% of people change plugs. The other reason is "because they can." The iridium plugs will foul just like any other plug, and cost 3x as much. If you change your plugs every 10-15k miles, what's the point in iridium?
I use plain old plugs in most of the XX's, and have no problems