Yes, I am going crazy without Mids. I am only L47 but it is still horrible lol.
"I have always been a fan of science fiction. It all started when my parents forced me to go to church when I was a child."
Make sure you consider the Dominator ATO set - the 6-slot bonus gives a lot of ranged defense.
As for other IO sets, looking at http://paragonwiki.com/wiki/IO_Sets .....
Consider both Pet sets and Recharge Intensive Pet sets for Haunt and Umbra Beast.
Consider to-hit-debuff sets in Fearsome Stare (might get you some recharge that you can drop elsewhere).
Stupefy in the stun for Ranged defense.
Lockdown will give some Ranged defense in either or both holds (though I prefer Basilisk's Gaze for the 4-slot easy recharge bonus).
Go into the database editor and change one of one of the powersets you never use to be a semiclone of the powerset you want (like dark). All you really need to edit is what IO set categories each power can take, then for each power you can edit important things you want to monitor, like recharge or endurance or whatever and then you can get the rest of the info just by looking in game.
You can also edit the IO sets to make the ATOs. All the set bonuses are already in the database, including the procs.
Mids doesn't update super fast, but that doesn't mean you have to wait for them.
Ok I'll try editing.
I'm doing Knives of Vengeance now and getting my *** handed to me. I really need to drop all SOs and get some defense.
I alternately swapped out powers from Fire Control and Mind Control to be able to place the sets where I wanted them. You have to drag some powers (like Terrify and Imps) to levels you can't TECHNICALLY place them, but it lets you look at the set bonuses. For the actual enhancements you just have to do the math with the aid of Redtomax since Darkness Control is there.
EDIT: It also won't give you access to all the sets available for each power but at least it's a start 
I agree, even in beta I realized Dark/Dark was going to be a tight build, much less thinking of what set bonuses I want. So far my Dark/Dark is only 28, so far a few more levels before I need to start to consider set bonuses( he's still on standard IO's, I prefer not to bother with sets until I get a power to 5 slots, and the 30 something level values)
My opinion of the ATO sets as a whole, and each sets proc varies, but IMO the Dom ATO set is a given, esp its proc.
Fearsome Stare, I can see very valid reasons loading it with a to-hit debuff set than a fear set
...until you can't use it.
I've got a Dark/Fire/Fire at 50 and just started Incarnates. I'm really struggling with hitting softcap for Ranged or Melee on this toon. Since I took the Fire epic I only have a resistance shield.
I know how to slot my Fire secondary well coming from a stable of other /Fire doms. But I just can't figure out the best sets to help me pick up some defense on the Dark primary.
Any suggestions?