I just got a Western Flyer (today!!!) and got a horizontal brain cache to go with it to carry my computer. I am feeling like it is a little overkill for my 15 inch MBP. I am going to be travelling to/living in Berlin for the next few months and want this bag to function as a personal item on the airplane (to go with my aeronaut) and to schlep around with me in daily life. I plan on carrying my computer, my shakuhachi (japanese flute), keyboard, camera equipment in a small case [I plan to put this in one of the front compartments; it is a small sony RX1]. Do you guys let it move around in the back or do you use the brain case or have you come up with other solutions altogether?