I'm a fighter who's found a really good dagger I want to use. Sadly, it's a light weapon and Power Attack has this unfortunate clause:
You can’t add the bonus from Power Attack to the damage dealt with a light weapon (except with unarmed strikes or natural weapon attacks), even though the penalty on attack rolls still applies.
So my damage tanks immediately. However, there is a clause in the weapon size rules:
The measure of how much effort it takes to use a weapon (whether the weapon is designated as a light, one-handed, or two-handed weapon for a particular wielder) is altered by one step for each size category of difference between the wielder’s size and the size of the creature for which the weapon was designed.
If my fighter was a medium-sized creature, and the dagger he wanted to wield was Large, he would wield it as though it were a one-handed weapon. But does this allow him to get around the Power Attack restriction and benefit from the damage?
I am not interested in house rules or DM rulings, but rules support only.