I thought about doing a little stress test, but I don't think I would get much info from it. I don't know how much stress the rods would see in flight, I also wouldn't know how the effects of temperature/time/repeated stress would affect the materials. The experience of others is plenty of reassurance. I did call a friend of mine who used to have a Midwest AT6 and he said that he used the plastic rods without any problems.

Ben