You are asking very very good questions, but the answers can only be determined upon each design setup. There are no generals, or basics when dealing with the factors of excursion control, and cutoff frequencies without having the specifications of the application known before hand. Not to mention that you have to also think "outside the box" literally.....and understand that even the driver loaded will have an effect on these parameters and limitations you ask of. So, there are answers to your questions, and again....very good questions, but non that can be determined based on only what has been presented so far. SO, to get the answers, you have to have a box idea in mind and what will be going into it at a minimum. I hope that helps!