Due to the flexible nature of the nap, it is necessary for sleepers to recognize the time they are naturally tired or drowsy in the day to place the nap accordingly; if the one's work schedule does not allow for a large range of nap time, then a smaller nap window can be chosen. Most importantly in this variant, late naps (after ~17-18) should be avoided because it may interfere with the core at night, which is more likely than on standard E1 as the total sleep time is higher.
