The two that repell each other are either the neck or the bridge pickups. The one that sticks to the others is the middle. This is because strats use opposite polarity pickups in the middle to create that hum cancelling humbucker type sound when the bridge and middle... or neck and middle pickups are selected...

As for which is the bridge and which is the neck... it's probably not going to matter too much because MIM strat pickups are pretty even with their output... I'd say wire it up and try it out and if you think it doesn't sound right just try it the other way... Chances are there isn't too much difference in the output between the bridge and the neck pickup though... the bridge is usually just slightly higher output.