Those pictured above will work but remember that access is a bit tighter in an enclosed trailer. I think the R-hooks work best in an enclosed trailer. There are several types of straps with hooks on them. I have a set with very large hooks on the ends that won't fit through the frame holes but work well with the R-hooks. There are also others with a double, round "thick wire" look to them. These work quite well when attaching directly to the frame. I'd check their on line catalog and call them, they were very helpful when I called for information.
Greg99ACRRedandSilver could probably get you the part number, he helped me with mine.
The squeeze toys just keep on coming to my house too.
Dan