Either Fatdaddy or the FT 10 pack.
Having a nemmy converted with the FT magnets, i say spend the extra money and get the FD set. With the FT magnets, you're going to need the 10 pack anyway, first because it takes 3 magnets to get a "stand on its own w/topper" button and then its becomes quite a stiff throw, and second because you're almost guaranteed to break at least 1 magnet during the process, theyre ridiculously fragile.
The FD kit only takes 2 and supposedly has a decent throw, and you'll get it quicker, but obv you'll pay more.