racing question!

question! I'm not sure if i should use my HED3 aero dynamic wheel for the Atomic Man duathlon in White Rock NM, or my light weight climbing wheel. The HED would be faster down hill, but the biggest down hill is so technical I usually can't get to top speeds without risk. I'm afraid wont get the benifits of an aero on the biggest downhill, but I would still get the binifits on the flat & other downhills. So, which wheel should I use?