[Chris Saper]

I think that Allan and Tom are on the money. North light is only relevant in the context of your painting hours.

For example, I only paint from 7:00 am to about 2:00pm. A western exposure would do just fine - the point is that you dont' want the directly moving sunlight to wreak havok with your studio light.

If my working time was late afternoon, an eastern exposure would be most suitable. In short, consider your individual easel time, your most productive time, and then make the judgement.