Meditation practices are so personal it's not possible to give you a "cookie cutter" answer to what you are asking. In general, it is good to leave that 20 to 30 minute gap between sessions to allow the energetic frequencies you have been working with to settle in. Any guidelines we give you are suggestions that you will need to adapt to what you have going on in your life.
For example, when I don't have time to do a longer meditation in the morning (which is my preference) I do Deirdre's 5 minute version. That works well for me.
If you have some high priority concerns in your life, then you might want to visit the "remedies" before you have practiced the other meditations for a week. Tweak your practice to fit what you have going on. If you do better with reminders throughout your day, then meditate several times. If you prefer to start your day with that reminder, then do that.
You might want to do consider doing some journaling during the first few weeks that you are incorporating the new materials to see what works best for you and then do more of that.
With regard to the 30 day guarantee, if you feel you need a little longer to incorporate the new materials and assess their impact, email CustomerSerivce@LearningStrategies.com and ask for an extension.
Enjoy your practice - however it evolves!
All the best,