I don't want to spend more than I need to. Are the flip crayons valuable to have, or can I do w/o them? Are groups of 6 students doable, or do you recommend smaller groups? I should have 1 of everything for each child in the group? Do you have all the groups working at once, and just rotate them through the various activities, or do you do one activity a day? Does the TE give recommendations for this? What do you find works best? Thank you for your assistance.