Ahhh, but that is the trick... Take the flip flop off. I drive barefoot or with as thin solved a shoe as possible. When I have dress shoes on (thick soles and less pedal feel) I'm not nearly as smooth. I will say this though, the manual in the Zl1 is much smoother and more forgiving than my SS. I'm having a tough time adjusting to the 6200 red line vs. 6500.
Never tried it barefoot, but I agree "big" shoes make it more challenging. Again, great car!