I have 2 supervisors who sometimes make conflicting points. We sometimes have meetings all 3 of us so we are on the same page. Recently I have asked for my supervisors to give me electronic feedback (in a Word file) which they send by e-mail and cc each other in so they know what the other one has said. Sometimes that creates a dialogue where one supervisor will say (I agreed with point X from supervisor A but not her second point because...etc) Otherwise I try to identify who (out of my supervisors) is more of an expert in each particular area, or I just go with what I think is best...you are the one that has to justify your work at the end of the day.