Honestly, it depends on what you want to use this build for.
If you want a more PvP-oriented build, you
need max Cold. And since Light is essential for a nuker (Mag Attack % + Parry Ratio + Speed + Grass Walk), I would say Build 2 is a more than decent PvP build, only cons being that you won't have the Fire nukes. But you can live with that, Light nukes are just as deadly.
If you're more of a team player, the first Build will work pretty well
if you switch Cold and Light around, so you'd have 60 Light and 40 Cold. Why? 40 Cold = 30% Snow Shield, which is enough if you're in a party (with at least a few Euros), while 60 Light gives you 15% Mag Attack, decent Grass Walk and Ghost Walk, and good parry ratio. So overall it would be good for FW, GW, jobbing, etc.
I would also suggest a third alternative, if you're not interested at all in 1 vs. 1 and you only plan on fighting in parties: The full-force nuker. Light 100, Cold 100, Fire 100. Insane damage with Fire nukes with the Mag Attack % from Light, great defense from 100 Cold + Parry Ratio, speed, status immunity... The works. Only downside, you get owned in 1 vs 1, since you have no Bicheon skills to KD and no Castle Shield series.
Cheers.