My Ultra Stick went through a couple of owners before the upper wing mount broke loose in flight. The only thing I reinforced prior to it's first flight was the landing gear plate. Looking back, I should probably have added a little triangle stock under the wing hold down plate. Everything else was fine. Then again, there must have been 300 flights on that plane before it packed it in. And I KNOW I flew it hard. I had a 2 stroke 78 in it.

If it's supposed to weigh 5 pounds and it now weighs around 12, you have likely gone just about far enough, I think.