Well if ya new to BLU and you're asking what would be a good set up considering that 2 of those spells are 80+, then something is wrong....

But if you want to work the spells to your advantage using a set up then you would kinda need to look at the modifier

for example Cannonball is 50%STR and 50%VIT, but since we tends to have quite a few STR gears we tend to balance it out to adding +VIT gears to boost the spell (not sure i'm explaining it right)

Charged Whiskers is a magic-based spell so again if you want more damage then you would need to lean toward a MAB (Magic Attack Bonus) set

But again it's very situational, depending on what you would like to do with those spells... personally i don't use cannonball pretty much now-a-days except for pulling for a party if needed be since it's has a good range for me to pull as my main solo-skill chain for light is now Savage Blade with Goblin Rush.