Yeah, the best time is when you typically find yourself needing a nap. Just be sure not to force it. Approach the WILD like you a normal nap, meaning if you don't even feel like napping, then don't bother with an attempt that day.

All that said, for most people, the sweet spot is in the early afternoon, around 1 or 2 PM. But that'll vary depending on your sleep schedule and daily activities.