I have bought over $900.00 in props, I live at 4200 feet and in the summer our temps are a regular 100 degrees. I have tried every prop recomended, and have found that at low altitudes the 27" menz or mejzlik work well but at my altitude it will not swing it. I get great 3d performance and great IMAC with a 26x12 menz, mejzlik and even the NX from air wild are great. So what I am trying to say is altitude and heat make a major difference on horse power. Just base your prop on altitude and you will problaby do just fine, and by the way I am the first guy at our field with larger planes so It is all a learning process for me. Hope you have a good time with your plane they are great to fly.