If you have to have a clean take-down design (read temporary set-up), take a look at this design. It's all about the end frames.
It uses 1" EMT (electrical conduit) for the legs and a 2x4 (on edge) top rail.
You buy (2) 10' sticks of 1" EMT and cut them in half for the legs.
You then chain and bolt your steel plates to the 2x4.
I use wing nuts for an easy takedown.
You can also screw a piece of 1x6 (flat) on top of the 2x4 for a shelf for 2 liters, bowling pins, etc.
https://www.shootsteel.com/products/2x4-hybrid-stand
This is their plate rack which is very cool as well, and it uses the same end frames described above.
The above pic shows their old style end frame.
I designed and had made locally the same thing.
Now, you'll get the new style which is shown in the first pic.
The best EMT end frame in the biz.
ETA:
If you try to go skinnier than 1" EMT it gets wobbly.
1" is the sweet spot for strength and weight.