Don't see the post quick, but I can describe it.
In this pic, there are gussets in the corners and if his had them, it probably would've been OK, but the red line I'd where I added a piece of angle iron to keep it from twisting. His was decent steel, but at 3/8" thick, it was just a little thin for the abuse the tractor could dish out. Yours is more powerful, so I expect the potential for damage to be greater. Just a thought.
I was actually thinking about the same thing. I have plenty of angle iron, and my dad has more of the bracket steel.
I found online where Brinly one bottom plows are about 68 lbs, is this about right?