Teachers
You don't need a master . What you need is some one with a good understanding of chess which is probably you . It is good to have others come in and give a simul or lesson but unless that person is gonna be a regular . He may not make any real impact on your students . I have coached and they were 8 to 14 years of age . There are some great books out there for the chess coaches or teacher with good techniques for training young people . Good luck I hope what I typed was helpful