In the anime, Argo's voice isn't gruff or gnarly so I'l be biased towards that, but if someone does a spectacular job with a gravelly version I'll definitely consider it. I don't want his voice to be monotone. It should sound serious almost all of the time, even if what he's saying is funny or kind. Take, for example, this gem. His voice should definitely sound older than Domon, Chibodee, and George. Also, it should carry well--have a bit of a boom or loudness to it (at least when he's intense).