I've grown a ton of AK-47. Its really nice pot with a good combo of head high and body stone. Very balanced and depending upon the individual plant, can be very potent. Some call it a one hit wonder.
On the light ... I've also grown with a 430 Watt HPS. For newly rooted cuttings and seedlings, keep the light about three feet above the plants. Gradually move the light down to about 18" above the plant tops. Keep it there for the entire grow. The 400 watter is an excellent choice for a small grow. WAY better than a 250 watter for sure.
Vi