Even though you tried to use the sim and didn't succeed in figuring it out, this is still asking other people to make your gear decisions for you. Both sims have documentation, you should be able to find the information you need. Then you'll be able to use them for future questions as well.
So I am fairly new to posting on EJ and am apparently not very smart when it comes to simming. I downloaded enh sim and just couldn't figure it out. I got the mace off Ultraxion last week, [Morningstar of Heroic Will]
and the 390 version of [No'Kaled, the Elements of Death] from raidfinder today. Clearly the raidfinder weapon is > 391 Gatecrasher, but I can't figure out which slot each weapon should go in.
Should I leave the higher dps wpn in my mainhand or swap it to the OH?
Does the axe have a high ICD which would make putting it in the mainhand for more attacks worthless?