It is best to think of it in this way: the hard cap on delay reduction from the cumulative effects of
all sources, i.e. Dual Wield, magical haste, job ability haste, and gear haste, is 80%. So, for example, if a DNC was using two 190 delay daggers (380 delay base), at 80%, the swings would function as if the delay was 76. You will not get any lower than that.
Because DNCs have such a high tier of Dual Wield, our gear should change depending on what buffs we have, i.e. Haste, Marches, etc. This is because Dual Wield still reduces our TP per hit regardless of whether we're hitting the 80% cap. So, to put it in extreme terms, using all of those equipment pieces you listed, plus Haste Samba/Haste/double Marches, we're effectively
way over the cap, but we're gaining less TP because the Dual Wield is still affecting our TP gain, and we're not actually swinging any faster because of it.
So, if you only have your own buffs, maybe a Haste (spell), the ideal set should be something like:
Charis+2/Charis Neck/Suppa/Brutal
Charis+2/Dusk Gloves+1/Rajas/Epona's
Atheling Mantle/Twilight Belt/Charis+2/Charis+2
If you are getting Marches, you don't need nearly as much Dual Wield (because you're capping delay and keeping excess Dual Wield will reduce your TP per hit), so you'd use something like this:
Charis+2/Rancor Collar or Agasaya's Collar/Aesir Ear Pendant/Brutal
Loki's Kaftan/Dusk Gloves+1/Rajas/Epona's
Atheling Mantle/Twilight Belt/Charis+2/Charis+2
Thus, you're at 80% delay cap, but your output is improved by weaning away the Dual Wield you don't need. (I'm very much labouring the point here, lol)
Hope that helps clarify it somewhat!
Edited, Jul 25th 2011 10:45am by Secretkeeper