Frozen orb sorc help

[nlm908]

thanks im going to go with a light sorc. the only thing is i dont knwo so mcuh a bout them.i know i want to use ES, and 117 FCR will not be a prop for me to hit,neither will the 86 FHR.the main thing i done understand is the whole ES and via ratio,but i saw that u said over 2k life is an over kill so jsut aim for that..?and then have around 5K mana? one mroe question then i think ill be good mags or frostburns? and coh or nig { i can get max res with out the 65 form coh } but is coh still best?
thanks for all the help man