The hard part is getting humans to agree on WHICH oil is correct. Even the manual isn't clear, it says above J so that means that the wet clutch motor oil from Castrol is wrong, yet it is made for a wet clutch.
Even what you say "use an oil designed for wet clutches in motorcycles" contradicts the Honda manual that says "above J"
SN is clearly above J, yet some are saying no.
My 2002 Factory Manual says SG or higher, EXCEPT oils labelled as energy conserving.
My 2005 Owners Manual says the same thing.
The manuals are very clear and contain no contradiction, as NO ENERGY CONSERVING OILS ARE TO BE USED.
While more recent specs can be used, what does not change is the exclusion of the use of energy conserving oils.
Keep in mind that for Mr. Honda, the dominant oil spec they invoke is JASO T 903 - MA.
API is secondary, and has to be, seeing as the API oil specs are for gasoline engines, not engines with bathed clutches and/or integral gearboxes.
What Honda is saying, to their credit, is select on the basis of a relevant spec that conforms to their requirements, and to help keep us out of trouble, run and hide from anything labelled as Energy Conserving, and if you want to make your life simple, buy a 'MA labelled oil in the correct viscosity grade.
A higher letter does not mean a better oil.
It just means a new spec has come along for a very specific set of reasons.
SN came out in October of 2010, is intended for gasoline burning engines of 2010 or more recent, that may be turbocharged, likely have rollerized valve trains, require less antiwear additive carryover into the exhaust re Cat' Con' contamination, and may see service on E85 fuel.
SNs are doped with energy conserving additives.
They have reduced antiwear additives.
Short story, outside of dedicated motorcycle oils, one is best left to buy a suitable API designated diesel oil also with JASO MA markings, such as Shell Rotella T6 5W40 . (So far, I have not seen any JASO MA 0W40 T6, but if I do, I'll switch to that.)