Hi, I have used gates at World's every year we've been and my horses have been happy and not had any health issues. You have to remember, the facility has to "clean" each and every stall after a group has left and they are preparing for the next group, NOT. I have noticed in the past few years that the horses that have ended up at the hospital did not have gates. These shows are VERY stressful, especially for weanlings and yearlings.
My husband is making stall gates this year. I don't have pictures as yet but I can tell you they can be either 36 or 48" high and 48" long. They are made of hog panels and tubing for frames. They are very light weight but sturdy. I have never been to Nationals but we are going this year
I was told by the show office that the stalls in Tulsa are wooden bottoms with bars at the top. It will be very easy to attach these gates. You will need two screw eyes and 2 double ended snaps.
Meadow