That's going to be tough to establish without a lot of really good data. Consider the fact that 2 cents of extra slippage on a 100 share lot costs you 200% of what commission would have been. 1 extra tick slippage on 20+ ES trades will eat up all the commission you'd have paid on the Pro account. It takes a lot of really precise data to show if Lite vs Pro makes a difference.
Obviously, trading styles differ, but for me, execution is a LOT more important than commission.