Here is what I think makes this difficult. This draft is deep at WR and OT. Do you take a tackle (would have to be Robinson or Mathews) that sees himself as a LT and play him at RT, where he is not going to be happy? Or do you move Glenn, to where he won't be happy. You kind of assure yourself that you will eventually let one walk. You could get a RT in 2 or 3.
The Bills really don't have a number one WR. If you take one at 9 it would have to be Watkins, maybe Evans. Then there is Ebron, would he be a better option the Evans? Can he platy a Jimmy Graham type role? Then go get a WR in 2 or 3?
What if Mack is there? Then you get a RT and WR later?