In regards to the mustard seeds, this is taken from the description in the Gnostic Store:
Black or Brown Mustard Seeds are used to protect the home from psychic attacks. Black or Brown Mustard Seed should be put in small containers in the four corners of the home.
Black Mustard seeds are also used to surprise and trap witches or sorceresses. This practice can be found in Logos, Mantra and Theurgy by Samael Aun Weor.
Obtaining the facts oftentimes requires a lot of patience, but yes you can carry out your investigations and receive guidance internally through learning to travel in the astral body.
When you begin to feel the separation of your astral body from your physical body just relax and let things happen, it is a natural process that occurs every night, we are usually just unaware of it.
Fundamentals of Gnostic Education is a work by Samael Aun Weor that is very helpful especially for parents and teachers. I would highly suggest studying it if you are looking for how to approach children or students with the teachings.