Hi. I've been practicing Kriya yoga for a long time, and I honestly can't recommend SRF. I have heard multiple times their teachings have been changed and are not the "original" Kriya Yoga of Lahiri Mahasaya. I just think you should look somewhere else, there are plenty of options, even online, there is a known free book that has shared basically all the secret techniques by someone with decades of Kriya yoga practice. Maybe you should start there! Cheers.