Good plan to make your own tomato cages, those pre-made tomato cages are junk.
Dunno about cattle panels and rebar, seems like it would be a bit on the heavy side...
Personally, I purchased a big roll of hog wire... a number of years ago.
Make all the tomato cages I wanted, and cages to support flowers that want to flop... problem is... it doesn't last forever... and wire is expensive...
By the way... I planted the running bamboo... all the stakes I can cut... just gotta go out in the spring and knock over the outliers... where it tries to spread...
