League winners will most likely just pick one of the two rbs and it will be the correct one...
If you take both RB of a RBBC say Johnathon Stewart round #4 and Deangleo Williams round #6 what happens is that you wasted two picks on two guys splitting time. If Stewart emerges then you wasted a 6th round pick only, either way it is better to take a solo RB and their handcuff in the 10th or later, or to take Stewart (or Deangelo) and live with the choice.