As an intermediate level sewer, I have learned that it is not possible to take clothes down more than two sizes because the grain lines get distorted, even it you were to completely take every piece of fabric apart & recut it, you're going to have to TILT the pattern pieces to get them to fit inside the old garment pieces...tilting means that things will hang oddly...and that doesn't look good. Sometimes creases, pleats, darts, and other old seams will continue to show - which doesn't look good. If you want clothes to look good after loosing a lot of weight - celebrate by buying a whole new wardrobe - making the old one over to fit the new you is going to make you look odd, not good. The fabric won't be as sturdy, it may be faded in the wrong places after moving the seams & such around, and it's going to look ridiculous to those who know what custom clothes look like and strange to those who just know what clothes look like...they may not be able to tell why... But it's not worth the money that it would cost to do that kind of work on used clothing. It might be worth it to wear your grandmother's wedding dress - but that's about the only time I'd even think to try...