I know you would have to strap with the wheel chock (any brand), but why would you think you need to strap using the pit bull setup? Something would have to break for the bike to move. I have put bull stands...they are not going to break.
Those Pit Bull Trailer Restraints are very popular up here. Lots of the race guys and some track addicts use them. I have the same 6x12 trailer you have and I'm toying with the same idea Baxley or Pit Bull. Either one works and you still should strap the bike down either way.
Flip a coin?