On single target raid dummy i get roughly 28-31k from both depending on how lucky i get i suppose but thats a fair range for both over several minutes.
However when i run scenarios with dw i average over then entire scenarious between 50-65k usually depending on how much multi target fighting is going on, single target in scenario 35-40.
I'm sure in raids ill do less because they are more heavily armored but i honestly cant see any reason to use 2h if most everything except boss fights are going to be multi target. Thats the only time 2s is better for me and its not even worth mentioning.
If you plan on raiding, I have news for you, boss fights are where your dps really matters. Also, raid bosses and scenarios are two separate beasts. With scenarios, you're basically beating up open-world mobs, so of course you're going to do more damage.
That being said, it all depends on what you feel most comfortable with. I play as 2H because I like seeing my Obliterate crits hit for 200k and up, but a DW player with similar gear would be able to perfom just as well. Oddly enough, even though they're so close in damage, they have fundamentally different playstyles. 2H tends to focus on large burst and hard-hitting melee attacks, since MotFW increases melee damage by 10%. 2H tend to stack as much haste as they can so they can generate runes faster and get more Killing Machine procs for Obliterate crits.
DW doesn't have the large bursts that 2H does, but makes up for it with better frost damage and better AoE. Remember, Rune of the Fallen Crusader doesn't stack, meaning one of those weapons can be used for Rune of Razorice, which increase your target's frost damage taken, making them more susceptible to your Frost Strikes, Howling Blasts, and Frost Fever. Because of this extra runeforge and reliance on Frost Strike over Obliterate, DW DK's tend to stack mastery to increase Frost Strike's damage, which increases Howling Blasts's damage as well.
Really, it all comes down your personal preference and the weapons you've got, and since it sounds like your weapons are at the same ilvl, feel free to pick whichever feels right for you.