so, supose I have all the dual weilding feats my question is:

would using a two bladed sword have a -4 ab penalty, the same as using two longswords?

or would it have a -2 ab penalty like when u have a small weapon in your off hand? It's -2 for all double weapons so it's often better to spend the feat for them, except maybe for dire mace. IMHO the worst weapon in the game. Bludgeoning is good, but it's like paying the price for exotics to use a simple weapon. Two maces would have the same -2 penalty. On my server you can find a decent mace but not dire mace and some servers take the term "exotic" to mean "essentially nonexistent."