Using the MET core rules, do the defense bonuses for using a Main Gauche and Fighting Style: Two Weapons stack? i.e. If I have a character with a main-gauche and one dot of FS:TW, does he get two dots of defense?
The main gauche is not detailed in the Mind's Eye Theatre rulebook, so any decisions made about its effectiveness are going to depend on the Storyteller's judgment. (For example, if the weapon comes from the Armory rulebooks, compatibility with MET is not assured.) However, presuming that it works in a manner analogous to the rapier (p.232), then the answer is "yes": using the weapon will offer an additional +1 when using that merit, at the cost of breaking when an Ace is drawn.