I have a set of boxed arms. I also had trouble with the brackets or arms bending.
I solved the arm problem by boxing them. As far as the bushing is concerned, you could use a press in ballistic joint and make a stronger custom bracket that is wider for more flex.
Anyway, no reason for that much round here so I just pulled mine out and am waiting for the weather to clear so I can put my staright axle under it!
If you are interested in the arms I pulled off, let me know!