Good info above. Yes magnets are well worth getting to grips with. They are very powerful but often ignored.

When I'm using magnets I try and get the majority of the manipulation done with just one magnet. I'll only add another if there is an area that requires fine tuning. With several magnets it is very easy to loose which magnet does what.

Here is an image of how I would set up a magnet to adjust the converted bikini. (I have used the Wardrobe Wizard smoothing tools.)

Starting with the magnet base. Position the base central to one cup of the bikini. Because the bikini does not face exactly forward I have rotated the base to align with the cup. Next position and scale the magnet zone so as to encompass the cup. I can now scale the magnet and hence scale the cup. Scaling follows the orientation and position of the base. This Is why I positioned and aligned the base as I did.

Magnet tutorial:-
http://www.philc.net/PTB_tutorial4.htm

On Screen video:-
http://www.philc.net/PTB_tutorial4.htm