Kam,
I beg to differ with regard to engine damage. I have the owner manual ( from the USA of all places ) and there is not a single mention of any limit wrt. WOT operation ( apart from recommending for fuel economy to operate at less than full throttle. ).
The engine itself actually contains a rev limiter which if engaged you should allow the revs to settle and then once again apply full power. ( their words not mine ).
I am sure Honda would mention if continuous WOT operation causes engine damage - especially in the USA of all places
I suggest therefore that my engine doesn't have any WOT limit.
Besides, if it were 1 hour, I don't think I have cruised anywhere flat out continuously for an hour in any case.
Finally, I would suggest that greater engine damage / wear will be brought about by using a prop which continually places a high load on the engine - bit like driving around everywhere slowly in 5th gear with your foot on the floor .