If the point of your thread is to test whirlwind weapons on a boss, I see nothing wrong with testing whirlwind weapons on a boss. I whirlwind bosses. I'd like to know how different weapons perform for sustained single-target whirlwind damage.
Post-fix, Shard of Hate was described by a blizzard poster as triggering both on skill use and on hit. This means it should get the best of all possible situations. Shard of Hate and Thunderfury both are described as having an internal cooldown, meaning that attacking multiple targets won't really provide giant increases in the amount of procs once you surpass an average of about one proc/second.
Odyn Son does not have an internal cooldown, but also has a much lower base chance to trigger (20-40%, versus the 60-100% estimated for Shard of Hate and Thunderfury).