-6/-10
With the TWF Feat
-4/-4
With TWF Feat and a Light Weapon offhand
-2/-2
You can take the Oversized Two Weapon Fighting Feat which allows you to use a larger than Light Weapon in your offhand and still have
-2 /-2
Unfortunately the feat wasn't implemented well with the small Races as it only corrects for medium sized weapons or above. The engine doesn't count small weapons as light weapons for small races. They will take a penalty for any weapon size larger than tiny.
From the wiki:
I've tested this IG and it functions as described. A halfling or gnome will take a -4/-4 if they have a small weapon like a shortsword in their offhand, and oversized two-weapon fighting won't correct for it. Is there any way the staff could modify the Oversized TWF feat to let small races offhand small weapons, or failing that add a separate feat for small races that gives +2/+2 if the offhand weapon is small?Oversized 2 Weapon Fighting and small characters:
A hin with oversized and twf has -4ab/-4ab penalty with shortswords in each hand.(Oversized does nothing with small weapons).
With oversized, twf and monkey grip with 2 rapiers he has a -4ab/-4ab also penalty.
With oversized, twf and monkey grip with rapier/shortsword he has a -6ab/-ab4 penalty.
But with oversized, twf and monkey grip with shortsword/rapier he has a -2ab/-4ab penalty !!!.