If you've ever had a client simply refuse to pay you for a two week contract ("sue me"), argued with a client for hours about whether a specification change was

If you've ever had a client simply refuse to pay you for a two week contract ("sue me"), argued with a client for hours about whether a specification change was "material", had clients decide your estimate changed T&M to a "fixed price contract" ... then even 2x is fools game. 2x is what I might charge clients I know for a low risk, low overhead project.