Well, I should "update" on how I trailer now, and I don't tie, ever. I have a two horse slant load. Sometimes if I have two horses that don't know each other too well I will tie the first horse up until I have loaded the second horse and am all ready to go on the road and then will untie the first horse. In the back stall of my trailer Casey has plenty of room to turn around, but always stays in one spot, but if she was uncomfortable she could turn around or to the side.
“Good things come to those who wait… greater things come to those who get off their ass and do anything to make it happen.” - Unknown