A rough EnhSim run with my current gear showed the 2x fist set bonus to be worth about 100 dps, and frankly, a wash versus a 2.6, 462.4 DPS Mainhand and
[Cookie's Tenderizer] for the offhand. All of those options still do not beat a caster mainhand (if you happen to have the right one that does more than 56 dps) paired with
[Cookie's Tenderizer].
Since the chances of all Caster Mainhand weapons eventually getting nerfed to 56 dps is fairly high (though timeframe is unknown) it's not a bad idea to pick up actual melee friendly weapons.
The latest EnhSim Alpha (2.2.8) does include the weapon set bonus as an option now, so your best bet will be to sim how your gear compares.