A Christian group of fly fishers that i am in tie at the Oklahoma wildlife expo we take on all comers. The kids line up 10 deep and stand in to get a chance to tie a fly. The older kids we coach through and the younger ones need a little more hands on like maybe holding on a tail while they wrap it. I generally let them pick out the colors and tie buggers unless the child has something in mine. We have business cards with a small foam square stuck on it to hook the fly in. the kids just beam when they get to hold the fly that they made.
We do it one on one with 6 to 8 men with vises set up. I would say recruit a few helpers