Yah, they are probably just a little bit too big.
But if you are buying these 10.5s because your old boots are too small for you, than you should. Don't force your feet into a 10 just to avoid getting new bindings.
Depending on the year and condition, you can probably still get a decent amount of money by selling those Cartels used. Then buy some new large bindings.
You may have to settle for Missions or Customs, but at least you will have a boot and binding that fit.