My experience is that MK is busier on the weekends. Well, all the parks are busier on the weekends -- but MK enough so that we avoid it. If you want to do MK on the weekend, I'd do Sunday.
However, our experience, also, is that the weekend before Thanksgiving, up through about Wednesday morning, isn't too terrible crowd-wise. We went last Thanksgiving (Saturday through Thursday morning). The crowds were really fine and manageable, starting to grow noticeably on Wednesday afternoon. Thursday was super-crowded everywhere we went.