I use this template to add in students names into the boxes provided. You change edit the types of instruments to fit your needs. I print this out and use it both in class and for concert preparation. This also allows you to better track performance grades when in a formation other than the seating chart.
At the beginning of the year, I print out 20 of these to put inside my binder. I write in any changes and use this chart to track performance based grades, turn taking on instruments, and behavior while allowing students to change up their formation and work in with different groups of people.