I am building a 2 story deck on the rear of my house. The deck is supported by a 2-2x12 girder through bolted to a 6x6 post set on footing at grade and a 2x12 ledger lagged to the house framing. My question is, how far can i cantilever the girder off the posts. I am in the need of about five additional feet from the post. Most codes state for every foot over bearing point you must have 2 feet back. The joists are 2 x12, 16" O.C. All framing material is #2 or better AC2 (gt). A link to a span or cantilever chart would be great or if you know from experience thats great too.

thanks