I always call them instrument fittings. Guess that may not make sense to a non-band parent adult if you’re looking for a better way to advertise them. I always talk to the kids and parents about how we’re looking for the instrument or instruments that fit the student best. Tell them some will fit well, and some won’t fit at all, and that the best fit will help the student be the most successful and have the most enjoyment. That spiel usually makes it pretty easy to direct kids (and parents...) to the best instruments for the kid, rather than having 60 million saxophones, flutes, and percussionists because those are the instruments kids have seen before. Lol.