boxing is a sport ... a game complete with rules, a scoring target and foul lines. there is no perfect defense because there's always an opening.
My bias is sidding up however for to make this research unbiased it must start by me convincing you that my bias isn't to side up. https://m.youtube.com/watch?v=yo56wI3qkMk The lesson is on torque if the feet are resting in a line then torque is sacrificed. The main reason mike Tyson had so much torque is the proper positioning of the feet. Inorder increase torque by 40 percent allowing oneself to easily manhandle a larger opponent it starts by getting into close proximity and using the elbow to guide your opponent. This was the physics behind Roberto Duran by standing normally both feet under his armpits at width apart Duran increased his torque. However it can't be done from the L-stance. https://m.youtube.com/watch?v=GJHtoa9nmn0