I think that the flex on one side or the other, and your too weak; that rear seems like you might tear it off.
You don't seem to have enough surface area for that main pivot point; It won't be good if it breaks off.
Too much side force and twisting. You can buy whatever diameter you need; DOM or other tubing.
Look in Speedymetals.com for one foot of either pipe, DOM or welded pipe etc etc. Your gonna need a buddy with a lathe or get yourself a 500$ Craigslist lathe; There on there!!.....
All our government does is distract us while they steal from us, misspend our tax $ and ruin our country