just to clarify, you only need one exp share. any more has no effect on your LC pokemon's experience.
if you're really worried about getting too much experience, switch in all of your remaining pokemon.
i only suggest this if you mess up and have to retrain at lv. 5 or something. you should be totally fine though, even ev training gen III eggs that start at lv. 5 with just one exp. share and switching in one pokemon to kill magikarp.