Does Glenn doman's method works? How about heregu or shichida? LO 15mo now

My eldest was with Shichida while my second is currently with Heguru. I feel that both methods are using alot on brain power and consistently exposing them to the same object to capture their attention. I cant say whether it works or not as my eldest has better memory retention at anything she sees. She was able to recog the memory cards v well, given the formed storyline. my boy, on the other hand, has v good attention span. he is able to see the flashcards and able to share with me on what he had seen, after his class. Both my children started the enrichment at 19 mths. I had seen some good progress but not able to tell whether i should contribute to Heguru or Shichidah as I teach them prior to letting them attend the classes.