What is the most critical bike fit metric - saddle height, handlebar reach, or cleat position - that beginner riders should prioritize to prevent long-term overuse injuries and optimize power output, and how do the current bike fit methodologies, such as the Level Motion Fit or the Wobblenaught, address this issue? Is there any correlation between the riders flexibility, riding position, and bike fit parameters that could be used to develop a more individualized and data-driven approach to bike fit for newcomers to the sport? Additionally, how can the performance benefits of a properly fitted bike be quantified and measured, and what are the key performance indicators that distinguish a well-fitted bike from a poorly fitted one, particularly in terms of aerodynamics, comfort, and efficiency?