How about:
90 pacheon
90 fire
70 light
50 cold
50 cold is the largest snow shield a 70:70 can handle, but it's substantially more than 30 cold. An extra ~15% absorbtion can only do you good.

The difference between 70 light and 90 light isn't that great, it's maybe a couple of meters in ghost walk, some parry points, and like 2-3 mag. attack %.
Overall, the larger snow shield definitely makes up for the loss of 90 light, to just 70.