you could try a 150 W HQI and mount it to a clock with small gear mounted to a large + gear to add toque. Give the dia of rotation about 10" and place that inside the hood.

That would be ideal. Every hour, the light would move around 10" circle.
Others have used 2x150W, or a combo fo MH and T5's or nothing but PC or T5's.

Really up to you, how much light you want etc.


Regards,
Tom Barr