I want to assemble a "check list" for hosts. In brief, the Stretch Therapist and Stretch Teacher workshops have the same basic needs, and the Monkey Gym ones need more; I will make a separate entry for these.
To begin, the area: about 2 square metres per attendee is a good minimum. Smaller than this, and the workshops begin to feel like a Bikram 'hot yoga' class!
We have worked in many kinds of facilities; one of the advantages of working in a Yoga or Pilates studio is that very useful props are to hand. This includes:
bolsters/blankets (one bolster per pair of attendees, minimum), and ask each attendees to bring a blanket; bolsters and blankets need to be thick enough to support a person's hip in the advanced piriformis stretch.
benches or Reformers (we use these for many exercises, particularly the variations)
chairs (one per attendee; these are essential for the Stretch Therapist workshop, in part two, where we emphasise the upper back and neck exercises)
sticks (we use a variety of lengths and thicknesses); and we use them in various ways, from putting in between the hamstring and calf muscles in a fascia rolling technique, to using shorter sticks as fascial stripping tools, to alignment cueing, to rotator cuff exercises, and much more besides; you get the idea. You need one sick per person, and a variety of lengths.
balls are very useful too, and again, various sizes and diameters. We like using the ones that can be inflated/deflated easily, and the Yamuna ones are the best, in my experience.
Tea/coffee making facilities. All hosts have different ways of doing this; Cristina Ferri, in Piacenza, engages a local barista who brings his own equipment (a pod-style single group head coffee machine, and delicious pastries!); Robin Truxel in the US hired a five-station coffee drip filter setup, and she provided nuts, fruit, and other nibblies. Basically, you need a hot water point, and things for hungry attendees to eat.
Tim Tams are required for Australian workshops!