weapon finesse by weight -- but what is a fair price?

[Fitz10019]

I want to implement this house rule:


Weapon Finesse automatically applies to any weapon that weighs up to 1 lb (such as a dagger, or a ‘lightweight’ version of a 2lb weapon); taking the Weapon Finesse feat increases your finesse-able range by 2lbs.

What is a fair price for a mithril version of a weapon? Or a darkwood version? The alternate material version would automatically be masterwork quality.

[Zexion]

What is a fair price for a mithril version of a weapon? Or a darkwood version? The alternate material version would automatically be masterwork quality.
Do you want the cost for mithril weapons? Because that's in the DMG.

[Knaight]

The issue isn't just weight but balance. A real rapier is on the heavy end, but they are balanced close enough to the hilt for it to not be relevant. Similarly there would be many lighter axes and maces, but those are balanced at one end. Of course, you could just do some multiplication of weights to take into account balance. Maybe x2 for end balance, x1 for mid balance, x.5 for hilt balance.

I would also allow strength to include what is finessable, and weapon finesse might just double that.