Another issue with the VO is the bar that attaches to the bag is solid steel. They make everything else from lightweight steel tubing, so this part seems stupid heavy. Attaching it to the bag should be the last thing you do, since it involves punching holes in the bag . Measure repeatedly, drill once.
i realized yesterday I have two different versions of this. One is older, I think, and it's a flat bar. Probably not as strong, but strong enough, and you could drill more holes in it. I haven't.