Yeah, I have my best results with WILD during naps when I'm somewhat sleep/REM deprived (5 hours or less the night before) but I wouldn't necessarily wait 5-6 hours to nap again (unless Puffin can show where she got that bit of info). Just give it a shot again after doing some stuff when you're feeling tired again.

Conversely, days where I got in my full 8-10 hours I find nearly impossible to get a productive nap from.