This is my approach of a DW Vindicator
at the moment (End of Elite) https://www.grimtools.com/calc/RZRql44V
goal build https://www.grimtools.com/calc/b28o63pN
To get DW ability, best choice i guess is this medal, https://www.grimtools.com/db/items/12131 unfortunately i only got the non-mythical version for now.
It grants me a 15% WPS which afaik hits with both weapons ontop of Savagery. Thats quite…low chance.
But then i stumbled on something which i never thought to want to use on my Lightning DW Vindicator:
Seal of the Void https://www.grimtools.com/db/items/8907 grants 16% WPS, but at first i dismissed it because of the nature of its damage type. But it has some attack speed (DW!) and even the fire/burn +% damage is not misplaced on a Vinidcator (Aura of Censure while having around -100% Elemental RR from different sources). Also the conversion physical to chaos will do no harm i guess.
Furthermore, like the WPS from the medal, it hits with both weapons and it can reach alot of targets because of its wierd nature of AoE. You can hit max 3 targets in 150° infront of you and those 3 targets are the center of another 3 360° 3m AoE. Devastating for monster packs. That looks quite intresting. All that with two weapons at once ontop on Savagery.
And…you can use two of them! Which leads me to some questions i have to ask because the first obvious component which came to my mind was Seal of Skies https://www.grimtools.com/db/items/8906 and i am short of materials, so i have to know it.
- If i use the medal and 2x Seal of the Void, will i end up with a total WPS of 47% right?
(15% medal + 32% seals)
Which would lead to a fairly amount of WPS i would say. For a non-2H Vindicator build. Ontop Savagery.
- Would it be better to go for more WPS instead of plain Seal of Skies on a DW Vindicator who refuses to go the obvious 2H path?
I am asking because i dont want to play 2H and i am bad at math, especially when it comes to WPS and Attack Replacer and Conversion and flat damage and all of that 
Thanks for reading and thinking.
(For now the only thing which would come to my mind is to test this on dummys,
2x skies vs 2x void)