Ya, that's one of the most effective techniques I've seen (as long as you still get the experience for it).
The creature's head does determine its class (warrior heads can have Rush Attack / Fatality skill bonuses, ranger heads have FireBall, and mage heads have Magic Missile / Magic Blast). I just automatically went with a warrior head (which was fine in Broken Valley), but at the start of the fjords I found it much more helpful with a ranger head, and I upgraded to a mage head as soon as I found one.
