ehm 18*5+
char)=roll 98
that's called cheating
even elfs rearly get roll 90
anyway
you need atleast 15 on you old prime (15 on str for you) and 17 on you new prime (17 on int)
Anyway i don't like kansei-mage coz you'll have to melee fight in which you can easely get interupted in your spell casting
Just think about it