My old trailer was a single wall construction steel trailer. The support beams ran on the outside. I had rings welded on to attach the hay bags, The Hi-Ties had steel supports welded on where i attached them, as the trailer had an opening that ran the length of the trailer, right at the height the Hi-Ties needed to be. I did not need to find support beams to attach anything, as they were visible, or I just attached bucket holders etc. where ever I wanted, with bolts and nuts, rather than sheet metal screws.
This trailer is triple wall construction. Outside steel wall, insulation, and then interior sheet metal wall. Support beams were not visible, and we needed to attach the Hi-Ties through the support beam to make them secure. Trails West was awesome to work with. I emailed them,and they sent me the blue-print of the trailer, showing me where the beams were. So, the first thing was to install the Hi-Tie on the passenger side of the trailer. That is the side I use the most when camping. I wanted this tie centered on the trailer. I don't want the horses to have the ability to look around the back of the trailer at the horse tied to the other side if possible. It just creates more issues. If they get used to NOT seeing the other horse, you can usually take one way from the trailer without the other horse ever knowing, and thus, they don't get upset when their friend leaves.
I think it even looks pretty good, and can't wait to give it a try. When used, the Hi-Tie will not be opened like in the picture, but be left folded against the trailer.