With most of the reinforced synthetic props nowadays, you're not going to see many (maybe any) badly out of balance. If you do, you need to check your balancing setup. If it checks out and you have found badly balanced synthetics, you need to avoid that manufacturer for awhile. He's got a bad die, or his hole reamer is out of specs or something. And his QA is not to be trusted.

I found a few APCs awhile back that all went INSTANTLY to horizontal. They didn't show when I loaded the first one, because I load horizontal. But the 2nd one instantly fell over. And when I saw it do the horizontal return with VENGANCE, I went back a checked the 1st one. When those were loaded at an angle, they went to horizontal QUICKLY and stayed. That isn't balanced. Why they went perfectly horizontal? They were perfectly out of balance is the simple reason. I'm guessing the hole reamer moves in two axis and the vertical was off. For sure the QA was off.

I've come to the belief that when a prop very lazily moves, I've got the balance within reason. And truthfully, nowadays, most systhetics are going to be that good. The woods I've seen in the last year, probably about half are good to go. Some of the others wind up being returned to the LHS.