I've had several trailers with the HiTie system and strongly reccommend them.  I've had to camp alot of nights where there were no trees or corrals.

I sleep much better with these than just tying to the tie rings on the side of the trailer

Paul,  That's an interesting way to look at it.

In the summer months when we go to high country. We have no problem finding trees to high line off. But during the cold weather when we ride in the desert. There are no trees.  So you either, put up an hot wire, tie to the trailer or use something like the HiTie.    I don't trust hot wires at night when I'm asleep. Horses push each other through the hot wire or deer/elk run thru and knock the wire down.  If I tie directly to the rings on the trailer, I feel every tug and get a horrible nights sleep. 

As far as height. I really like to get them up as high as possible.  But 7' tall trailers especially if they have anykind of a radius on the roof,  Often max out how high you can mount the hities at 6' or 6'6". With a tall horse, that's just not high enough.  I'm 6'2" and with my long arms I can reach 8' high. And that is where I prefer to mount my HiTies.  A shorter person will have to get some help ( in a stool or step ladder) to extend and lock in place Hities that mounted that high up. But I think that is worth the effort.

Regardless at what height, The units are mounted, I'm going to tie my lead rope at such a length that the horse can barely stretch/flex the unit to touch his nose to the ground direct;y beneath the tie point. The higher the unit is mounted, the longer the lead can be and still not allow the horse to touch the ground.  The longer lead hanging from the tie allows a greater circle for the horse to move about with in. Essentially giving the horse a larger circle to walk/move about in.  I also often ride attach/remove the lead rope while I'm in the saddle, So I prefer the rod to be high enough that it won't scrape me off the saddle if a horse turns or dancing while next to the trailer.  It's all personal preferance. But I like mine as high as possible.

The HiTies come with a bungie connector for the connections between the Fiberglass Rod and the halter.  I never use them.  I just attach my lead ropes driectly to the fiberglass rod.