Baleing twine, baleing twine, baleing twine!
I cannot say that enough
It has helped me out SO MUCH tying in the float, to the float and anywhere else I need to tie.
Just recently my horse decided to "redecorate" the float and thankfully he was tied to baleing twine. He managed to turn himself around so his head was sticking out the tailgate. I don't want to imagine what could have happened if he wasn't tied to twine.
I've had a few float incidents that have turned out a lot better than they could have if I didn't tie to twine.
No matter how breakable your halter, lead rope or what-have-you is meant to be, in my experience, it isn't always that breakable.