I have a question regarding which off-hand might work best with WW in general.
So we know that WW takes its damage from the weapon you about to swing while RltW takes it from the last weapon swung.
Let's say I have an echoing fury as MH and a dagger in my OH.
I want to know how this will affect my dps.
Please answer these questions for me:
1) First let's start with WW. If I'm about to swing my dagger and I WW through the mobs it means that my WW will do the dagger's damage right?
2) Secondly, if I swing my dagger last it means that I will take my damage from the dagger with RltW?
Now if the answer to these two questions is YES then it means that having a dagger (which is low dps) I will make everything tick more often but with lower dps.
3) Is it better overall to have an echo + a slower weapon (mace, spear) with a higher base damage that I can hit everything harder? ...and do better when adding HotA into the mix.
Usually when I dual wield I like using basic WW setup mixed with either HotA or Rend. I rarely go pure WW (with overpower that is).
I need to correct you a little. RLTW doesn't take damage from last weapon swung. It takes APS from it. It always uses MH dmg.
WW simply alternates weapons (so does HotA). This makes your questions wrong as well, but i will still answer them.
1) WW simply does ....MH - OH - MH - OH ... etc.
2) No, always from MH
3) Nowadays it is common to have EF in OH, because it fears less often and because the dmg of it doesnt go as high as a rare mace or possibly axe would in a similar price range (you want high dmg in MH).
Yes it's better to have hard hitting weapons when you use HotA, stronger than a dagger at least. OH doesn't really matter on bosses or anything that dies slowly (DPS is what matters there, smaller hits are made up for with higher APS), but in general it's still better to have weapons of about similar dmg ranges when using HotA.