I just got back from 6th grade camping trip and against the will of the teacher organizer I brought my 3wt along. While fishing the pond, the kids would come up to watch and I asked them if they would like to try to cast. I tried to teach them the concept of casting a fly rod. The camp counselors were also interested in learning. Granted I am not a certified instruction and not a great caster I am a decent explainer of the concepts. So, based upon my recent experience, SPIN SPIN SPIN. You will take all of your time teaching folks who may not be all that interested in fishing, how to master a pretty complex athletic move. Think back to when you started...
If they have limited experience you may be spending a ton of time untangling spin gear.
SPIN SPIN SPIN
My $.02