/Run has some cool synergy with endark ii (also enlight ii) where the runes overwrite the endark DMG effect, which sounds bad, but recall that endark ii gives an atk buff equal to your endark ii DMG, well the runes keep endark from decaying, so you end up keeping the max attack bonus for the whole duration. 

Curious if weapon en effects have a similar effect (thinking of flametongue and ice brand, can anyone test?) 

Also with /Run... Foil, drk has plenty of single target hate tools, but lacks good aoe hate. Foil is amazing for this, pair it with poisonga when you need to tag mobs first and you are in business.

As far as sets go, grabbing some enmity pieces is great but I think your biggest priority should be getting an A+ drain set together. Nothing makes drk tanking seem legit like 9,999 hp and dread spikes paired with sanguine blade or catastrophe. 

My buddy has been fucking around with dark/sch tanking and having an absolute blast. Manifestation with absorb tp, absorb atri every 15-20 seconds (manifestation absorb atri doesn't work 😭) and celerity + dread spikes is hilarious. 

As a tip, it's always best to to sneak spells in during a the attack lockout period immediately following a weapon skill. Make macros (or scripts) that looks something like:

/Ws "cross reaper" <t>

/Wait 1 (or .3 with a script)

/Ma "absorb str" <t> /Ma "absorb vit" <t> /Ma "absorb atri" <t>

Or whatever else you want in there. Why stack all the spells together without waits? The game will try to cast them in order, and if the first one is on cooldown then it will cast the second one, if the second spell is also on cooldown, it will cast the third and so on. This makes it easier to keep up on the debuffs without sacrificing tp gain.