I have generally found that magnets, with practice, can get you pretty close. But there are areas that will require multiple magents. It seems that using several smaller magnets works better than trying to do it with one or two big magnets. In addition, the nipple location changes when the breast size changes, so this has to be reworked. I usually end up exporting the morphed and modifed clothes and tweaking the mesh directly. The main problem I have with directly editing the mesh is keeping it smooth. That is probably a problem with the technique I use.