I have done a few Demo Days where you can try a few different shafts, etc. but a full bag fitting is a completely different animal. Be prepared to work. It takes time and you will make a lot of swings. I took over 200...The information learned may surprise you. The only thing I would do differently is to break up the fitting into two sessions, but I live 2 hours away from the location.
I was not looking for additional distance (in my irons) but higher apex and better dispersion. Both goals were met!