Hi firefighter56,
I'm also building TF P-39.
You leave the leading edge of the elevator only during the building - its just easier to glue all ribs. And then you cut the central section because elevator halves will be joint with the wire. [8D] You may look at my P-39 fuse, at this moment I'm building the wing.
As for the engine location:
"William J. Herrmann, Summerville, SC built Bell P-63A King Cobra 8-foot wingspan with 87-inch-long fuselage, and William powers it with a Moki 2.10 engine, which he has cleverly mounted in the scale location-behind the pilot! William also directed the airflow from the fuselage scoop and wing scoops to the engine compartment. He created a vent on the center-box bottom so the air could exit during the engine's cooling process. He also constructed this model with working cockpit doors, retracts and wheel doors. It took William two years to gather the information and build the King Cobra." (From MAN magazine)[8D]