People seem to have forgotten something here.

There is no need for the weapon to be of the blunt variety. What you face are Stone Golems, which merely needs any weapon that is +2 enchanted or higher. As such, even Arrows +2 will suffice or Melf's Minute Meteors, Chaos Blade +2, Lilarcor +3, etc... ...
As far as I know, there is no time limit to kill the Cowled Wizard.