Hi...don't rush it...if lo needs a nap, it's better to let a spirited have a nap then get bent out of shape and over-tired...My lo is 9 months old, and on the 4 hr easy, but sometimes needs an extra nap...especially if we are in a busy enviroment...I would rather let him nap then let him get overloaded.
With spirited babies, they actually need their naps during the day in order to prevent overload and have them awake all night...
Try to stick with the 4 hr easy, but use the lo as a guide, sometimes they need an extra nap...