Hate to say it but I think your DH's idea of square, with your idea of a wall down the center might just be the hot tip. Can he get his wood shop in the other half of the building? I would think rectangular would work better for that application as well. Just make sure you put LOTS of insulation and plastic sheeting over the insulation when doing that center wall if he's doing wood working in the other half. I'm sure you know how much sawdust THAT produces and you wouldn't want that mixing with your machines/quilts.