Stir Plate Questions

[Mexibilly]

I was lucky to find everything I needed for a stir plate at a nearly empty radio shack.
My questions:

1. I have 2 fans, a .85 amp smaller fan and a 1.3 amp larger fan. My switch is 30 amps, rheostat is 25ohm 3 watts.
Is there any reason to use one fan or the other and will the draw from the larger be too much?

2. I have 2 larger magnets and 2 slightly thinner ones.
Is one size preferable to the other, and should I use one or both of the pair I choose?

3. How best to separate the magnetic force from the motor components? The slightly larger magnets affect each other with one on the palm side of my fingers and the other under my hand.

I guess I think a bigger fan with 2 of the larger magnets stacked would be more effective on a 3,000 ml flask if I were making a huge starter with old yeast.

I've seen threads with one magnet, threads with 2 magnets stacked, threads with one magnet broken in half and placed 180 across the fan, multiple threads with washers glued to the fan and magnets attached, threads with cardboard between the fan and magnets.
I'd prefer to get this right the first time.
Anybody have a stir plate they've made that's lasted for years with no problems?

 

[Smellyglove]

I've tried a few configurations and landed on stacked magnets. Before I had them spread out along one axis but it couldn't pull a thick starter (slurry) in a 5L flask. I stacked them and now it pulls way better.