No pretty charts this time, mostly because I have no simple answer for it.
The best advice I can give is if you have all of the following:
1: Between 40-46% self-buffed crit.
2: More than 40-45% self-buffed mastery
3: A Thok's Tail Tip of 570~ ilevel or greater
Then windsong on both of your weapons is very likely the best weapon enchant for you.
Once you reach 46% self-buffed crit, in most cases double dancing steel will start to become better, and will undoubtedly be better any higher than that. The amount of mastery isn't important at this level of crit.
However, the only way to be sure is to simulate your character and find out.