^
This sort of matches my experience. My TTs are mostly on smooth courses and the random Flo deep front that I have matches very nicely with a 25c Corsa Speed. I'm a 27-28 MPH ITT kinda guy and 29-30 MPH TTT guy. I have a Zipp Super 9 in the rear with a 28c that bulges a little, but I keep it for comfort and don't mind the aero matching as much since it's not the leading edge (front).

I'm a smaller dude at 65 kg and although my w/kg is high, my absolute watts and early stage optimization put me a notch or two below the supersonic TT guys. Still good enough to get me 3rd overall in the Valley of the Sun Stage Race last year in the 35+! 10 mi TT day one.