got myself a hybrid int spear char as well, but it's primarely fire based (more focused on dealing heavy dmg rather then low dmg and slowing mobs down).
i'm currently working on hybrid char to use both the fire as ice imbue, as i can both use phy as mag based attacks rather nicely i'm starting to think about using fire for mag based attacks and ice for phy based attacks.
so basicly my spear skills will use ice imbue later on, and my nukes will use fire imbue (and/or mix it up ofcourse).
but whatever makes your boat float dude, then just go with that

i would suggest using the fire imbue first and like me add the first level of the 2nd book of ice imbue later on.