i wouldnt use the ones on the right for sure, the left ones would certainly be strong enough, but they are too big imo. I think they might keep your fan from turning. I know some have gotten the smaller rare earth ones at radio shack and ace. got mine at harbor freight.
Mike in Duluth
Currently on Tap
2. BM Centennial Blonde
3. LHMS Clone
Next on Tap-Denny Conn Rye IPA
Kegged and aging Ed Worts Apfelwine, Denny Conn BVIP
I can say for sure the ones on the right will not work. They will not be strong enough. The ones on the left, well I cant tell. I know you need a rare earth magnet. I think they are different from the one on the left though. I'd do some research first. When I built mine I purchased 2 rare earth magnets of a website for next to nothing. I think shipping them was more $.