Fixed Time Trial Bikes

To what extent does any of this really matter when sitting immediately behind any configuration of head tube/base bar/extensions/risers is something massively larger and less aerodynamic (no reflection)?

Relevant to this, my aerobar set up is probably slower than a nicely integrated setup, but because it allows me to get my arms closer together it's probably (hopefully?) faster overall. A decent position on chunky bars will be faster than a crap one on USE R1s.