I recently purchased and installed a Primus Air 40 on a 20' pole in a moderate wind area that is occasionally subjected to very high winds. I'm pleased with everything but the composition of the blades. I doubt the plastic(?) will hold up long in our extreme sun. I'm considering replacing them with aluminum blades from WindyNation, but do not know what size or style (if any) would be appropriate. I'm sure more details are needed to respond (unless you happen to be familiar with the Air 40), so please let me know what other details would be helpful. I'll try to provide them. Please note that I'm not an electrical engineer or well versed on anything electrical. Any advice would be appreciated.