the problem with the container vs the light is temprature, you don;t want to cook them
you have to use a thermomiter to figure out just what light you need
if you do use a containter like an aquarium or even a rubbermaid tub, you can get possibly by with a 40 wat bulb, those 250 watt bulbs are designed for a large space. we use wire dog crated with cardboard as draft sheilds, and a 60 watt bulb does fine in ther.
day old chicks should be between 95-100, (we kep ours cooler, about 90), and temp should be decreased 5 degrees each week until te are at 70.