My mom used to sew in the basement and was also toying around with the idea of keeping her sewing room downstairs but then decided after moving all of the computer stuff into the other room that she had my previous bedroom all to herself and she is much more happy now. She has more light and when her joints don't really like the stairs she can stay upstairs and sew to her hearts content. She still has her mid arm downstairs as that is where it has always been.
But back to your question, I am not really sure if I would want to stay downstairs to sew all of the time or not. I really enjoy the natural light that I get from the window and I only really get alot of sun in the late afternoon, so I am blessed with just light natural light for most of the day. I would really miss that light if I was downstairs. But if the sun is not out and it is cloudy, you still have more light then than if you were downstairs anyways. But if you want extra light then I would get some Ott lights they are wonderful to use and give great light to any situation. I would probaly also move the couch and other things, except for the dog bed. You can put the dog in the corner by the sewing machine. Mine likes to sleep under the ironing board, go figure. I would be worried that I would get hit in the head by the iron. Oh well. Hope this helps, was a bit long winded. sorry.
