It is true that at faster speeds 2 blade heads can plane or cause a lift.But with the newer BH out today you realy don't have that much of a problem.
Not true , the less blade you have up front the getter flight you will have . Most but not all 2 blade heads are smaller , have less area than 3 blade heads and fly better . If your arrow launch is not straight and level , the more area you have up front will stear you arrow harder .