I don't think Floyd is significantly bigger than he was against Judah or Baldomir.
The only difference is that with the 154 weight limit, he can enter the ring at the exact same weight that he weighs in at.
He doesn't have to get down to 147 and then add a few pounds back on before entering the ring. He's probably been sitting at 151-152 pounds for his entire training camp.

Whereas Oscar has been losing weight, and will likely add on several pounds thru rehydration after the weigh-in.
If Floyd weighs in at 154, then I will take that as a bad sign, but he's at 150-151, that's right where he needs to be.