What you are trying to do is equivalent to getting fitted for a custom suit via an internet message board.

Why not go down to a bike shop and get a proper fitting? If you don't know what you are doing and don't know what sizes you need, there are people that do. It may cost a few bucks, but it will be less than buying a bunch of the wrong stems till you luck up and get the right one.

BTW, "quite a bit longer" makes it sound like you may have bought the wrong sized bike, too. This wouldn't have happened if you tried it on before you bought.

Sorry, man. I'm just calling it like it is.