Clefables standard movesets are mostly special.
That should work well in UU, though Abomasnow will ruin your fun with Hail, and Grass Resist. Put Fire Blast over Rflct/LS to counter. As far as standard play goes, Blissey, dragons, Ttar, Hippowdon, Heatran, Gyarados, Heracross, random walls, other random stuff all mess up this set. You could try it, but I doubt you'll get good results. In my experience, the only clefable set that ever worked in standard was the calm mind version. And that was in ADV standard, so I'm sure it got even better with Magic Guard.