A little input from 40 years of hauling dirt bikes. If you are hauling on a rail trailer, especially if it has little or no springing, then tie the rear tire in the rail (as well as of course the handlebars). Don't ask me how I know this. I carry my KDX all time in a pick up with a 6' bed. Either leave the tailgate down or put the bike in a corner, angled in the bed, and you can close the tailgate. I prefer this arrangement and suggest that if you do this, then triangulate the handlebars by using a third tie down attached to the open rear ring.
The nicest thing I have discovered recently is the tie down "figure 8 loops" made of nylon webbing. You just loop these around your handlebars and hook the tiedowns into the loop. Street bikers use them for transport all time. Does not bung up your tiedowns on the triple clamps nor skin up your handlebars. Sometimes enduro riders with their equipment do not have room to hook the tie down in the handle bars anyway!
Just load up and go ride! John