Playing your best OBP guy is the correct use, yes. Since Ref sucks vs RHPs, yes, you force a platoon on whoever deserves to sit more: Duran, Dugo or Yoshida, but yes, Ref needs to start every game vs a LH'd SP'er.
IMO, Duran deserves to sit the most, due to Ref sucking in RF, and Yoshida hitting LHPs better than Dugo and Duran. I'm fine with matching it up, so Ref does play in RF and DH when those two get a day off, and that might get Duran 10-20 starts vs a LHP, but to start the yea, I see Duran being the odd man out- most of the time.