Hou Niao could brush about ten artifacts in one hour, and many factors determined the speed at which he brushed, such as the replenishment of mana consumed, the speed at which the Sword Seed accepted and absorbed, control and shaping of the Sword Seed, and from now on, the cultivation of the Sword Spirit...
But this speed wasn't constant; as he became increasingly familiar with the process, his speed accelerated, and the rate at which the treasures of Wu Sect were devoured also quickened.
It was impossible for him to spend all twelve hours of the day on his private affairs; he had to come out now and then, walk around, and go through the motions of inspecting others' work, which was his responsibility as the supervisor.