Here in UK many are made by wood workers. They are solid and adaptable. They also come down quickly.
The beam across is specific length and we have to put on a4" sleeve. And with the holes in the main upright and beam can adjust height. Width stays the same.
The bases not sure how they fit someone else would know better.
I have seen them coming down faster than quilts.
The wood is treated in various ways.
I have used the stands used by photographers but they are too light for a major show. One show had used wood across sleeves and been pulled up on rope pulleys. They were hanging at all different heights.
Must improve drawing. Hope it gives you some ideas.