Actually, you don't have to orient both cones into the prop. Just place the two cones facing the same direction on the shaft. One goes into the prop and centers it. Since APCs say that one side is not precisely centered, face the imprecise side away from ththe cone going into the hole. The other cone's flat face will provide perfectly adequate pressure for both cones to hold the prop accurately and firmly.

This is done all the time with props that are too thin to allow both cones to project into the hole without interference.