I just started playing my level 52 mage again and realized that I'm not only rusty but my build probably needs some tweaking. Right now I have points in arcane up to arcane concentation and the rest in fire. And I only play solo pve. I like the idea of the 2/48/11 build because it would give me a little more defensive capability with imp frost nova. I'm just not sure where to put five of the frost points. The two variations I've seen put either 5 points in imp frostbolt, or 2 points in frost warding and 3 in frostbite (the remaining points go in elem precision, imp frost nova and icy veins). I'd appreciate any input from someone who has tried either or both. Thanks.