I usally take about 60% of my daily dosage first thing in the morning, then the other 40% mid-afternoon, no later then 4 or 5 Pm though, otherwise no sleepy sleep at night!!!
Doesn't matter since it stays in your system for so long. Just find a schedule that minimizes the sides for you. I take 10 /day, 6 in the am, 2 around noon, and 2 around 5-6 pm.