I'm big. 210-215ish @ 6'3" so potential energy is my friend.
I crest the hill as far back in the saddle as I can comfortably sit, providing me with a slightly longer descent than those around me that are forward hugging their headsets. Longer descent w/ more mass = faster descent. (HA!)
I get aero by grabbing the clip-on bars and tucking my elbows into my chest/stomach. Usually still seated but occassionally "standing" on one pedal (assuming I cannot pedal any faster or I want/need a break) with my backside as far up & back as possible.
I have used a "lean really far forward" approach but found it to be a bit less stable, although possibly faster.
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