1) If there are gaps in your work memory, then try to reflect on those moments you do remember.
How fast or slow you review the events of the day depends upon your intuition. Follow your heart. What does your Divine Mother want you to reflect on the most, to seriously analyze? Review in accordance with your spiritual inclinations.
Regarding meditation on any object, we must always be profound, whether we seek to understand a symbol or an ego.
Concentration is fundamental. Without it, we cannot access real meditation. If you struggle with the Tao meditation, perform concentration exercises as detailed in the Gnostic Meditation course, such as fixating your eyes on a candle and watching your thoughts. Simply observe the candle.
Vipassana means special insight, which we can develop through practices with imagination, visualization, and concentration. These are good preliminary practices for helping us establish the foundations of religious practice, but they are not the goal in themselves. Afterward, we must go deeper, such as the Tao meditation and psychoanalytical practices given by Samael Aun Weor, since these exercises pertain to the Mahayana and Tantrayana levels of esotericism, and are superior in scope.
Journals can be very helpful. I have worked with them for years!
2. Regarding the suspension of one's practice, we in turn retrogress in our capacities to concentrate and visualize when we, as the consciousness, slack in our discipline. The skills for meditation are within the consciousness, and depending upon our discipline, whether on retreat or in the city, we can access those states that we might have previously developed in past lives or our current life. Only if we reinitiate our efforts to reach and maintain those states we lost, can we return to that level of concentration. Remember that nothing is static. We reach a certain level of being, stay there, or move higher in accordance with our work. It is up to us. Now, if we can maintain a high level of being in the city, our level of concentration and willpower will be greater than if we worked in meditation on retreat, since the former circumstance requires greater discipline to produce and maintain than the latter.
3. Those authors you mentioned are excellent and highly recommended! Yes, I do not tell students just to read Samael Aun Weor, because it's important to see the unanimity of perspectives on esotericism from the great initiates. It is sad to see some students and missionaries of this gnostic teachings who only read Samael Aun Weor and become very fanatic, demanding that students only read his books. Meanwhile, our Guru Samael Aun Weor told us explicitly to stud the writings of Swami Sivananda, Dion Fortune, and others as part of our spiritual education. This is part of developing a robust intellectual-spiritual culture, which helps us from being misled, as Samael Aun Weor explained in Fundamental Notions of Endocrinology and Criminology
When I read other authors like those you mentioned, and when I compare their level of knowledge and perspective, it gives me a greater appreciation for the wisdom of Samael Aun Weor, because the depth of his writings are tremendous and very clear, which is refreshing if one has proceeded out of a labyrinth of spiritual authors and writings. Reading works by the great initiates also helps us understand the universality of this teaching, and helps us see how much Samael Aun Weor really knew and taught.