1. Is there any harm in using entrainment for that long in a day?
Not that I know of. The only time when entrainment might be a bad idea is when operating dangerous machines or in traffic, as it may infuence your concentration. All entrainment does is create a resonance that your brain tries to follow, thus slowing down your brainwaves to a more relaxed state.
2. If I use LF series during my meditation and later on want to meditate without it, how difficult will it be to get into the meditative states without LF tracks? I'm asking because there may be situations when we may not have access to the tracks.
Your brain actually remembers the progress you have made as a meditator, and LF just speeds up the process significantly. If you meditate without LF you will probably reach the same state as you are used to, but it may take a bit longer than usual, so you may have to extend the time of your meditation for similar results. LF is no miracle cure, so in the end the meditation and its benefits come from you, LF just helps you do it a bit faster.
Enjoy your meditations, and meditate every day !!!!
